Programming Notes

2/3/2015

1

Copyright 2009 Troy A. ZindermanStructured Programming Using Procedural Languages INSS 225 Overview of C

Review of CReview of C

Week 2Week 2


A C ProgramA C Program

/** Converts distance in miles to kilometers.*/

#include /* printf, scanf definitions */#define KMS_PER_MILE 1.609 /* conversion constant */

intmain(void){

double miles, /* input - distance in miles. */kms; /* output - distance in kilometers */

/* Get the distance in miles. */printf("Enter the distance in miles> ");scanf("%lf", &miles);

/* Convert the distance to kilometers. */kms = KMS_PER_MILE * miles;

/* Display the distance in kilometers. */printf("That equals %f kilometers.\n", kms);

return (0);}



intmain(void){





return (0);}



intmain(void){





return (0);}



/* printf, scanf definitions *//* conversion constant */

intmain(void){





return (0);}

#include #define KMS_PER_MILE 1.609


Preprocessor Directives


2/3/2015

2


Preprocessor DirectivesPreprocessor Directives

A C program line beginning with the #

symbol that provides an instruction to the

preprocessor.

Preprocessor a system program that modifies

a C program prior to its compilation

Two most common directives: #include

#define

A C program line beginning with the #

symbol that provides an instruction to the

preprocessor.

Preprocessor a system program that modifies

a C program prior to its compilation

Two most common directives: #include

#define


The #include DirectiveThe #include Directive

This directive identifies that the program will be using functions and/or symbols that are located in a library file. The directive will cause the preprocessor to include the definitions prior to compilation.

In the C language, libraries of common functions are called Header Files and their names end with the symbols .h.

For example:

This directive identifies that the program will be using functions and/or symbols that are located in a library file. The directive will cause the preprocessor to include the definitions prior to compilation.

In the C language, libraries of common functions are called Header Files and their names end with the symbols .h.

For example:


The #define DirectiveThe #define Directive

This directive associates a meaningful name to a constant value to be used throughout your program.

These meaningful names are called Constant Macros and greatly assist us in understanding the logic in the program.

For example: #define PI 3.141593 #define US_LIFE_EXPECTANCY 77.7 #define US_AVG_INCOME 50233.00

This directive associates a meaningful name to a constant value to be used throughout your program.

These meaningful names are called Constant Macros and greatly assist us in understanding the logic in the program.

For example: #define PI 3.141593 #define US_LIFE_EXPECTANCY 77.7 #define US_AVG_INCOME 50233.00

2/3/2015

3





intmain(void){





return (0);}



intmain(void){





return (0);}


/* printf, scanf definitions *//* conversion constant */

/* input - distance in miles. *//* output - distance in kilometers */

/* Get the distance in miles. */

/* Convert the distance to kilometers. */

/* Display the distance in kilometers. */



intmain(void){

double miles,kms;

printf("Enter the distance in miles> ");scanf("%lf", &miles);

kms = KMS_PER_MILE * miles;

printf("That equals %f kilometers.\n", kms);

return (0);}



Comments


Program CommentsProgram Comments

Programmers can add additional descriptions

and explanations on their processes via

Comments inside of their code.

The /* and */ symbols are used to identify

the comment. Text between these symbols

is ignored by the Preprocessor & Compiler.

For example:

/* This will be ignored during the compile. */

Programmers can add additional descriptions

and explanations on their processes via

Comments inside of their code.

The /* and */ symbols are used to identify

the comment. Text between these symbols

is ignored by the Preprocessor & Compiler.

For example:

/* This will be ignored during the compile. */

2/3/2015

4


Program Comments (cont.)Program Comments (cont.)

An alternative to using the start and stop

symbols, is to use the single line comment symbol of //.

When using this symbol, the text written on the

same line in your source code is ignored by

the Preprocessor & Compiler.

For example:

// This will be ignored during the compile. This will not be ignored during the compile.

// This will also ignored during the compile.

An alternative to using the start and stop

symbols, is to use the single line comment symbol of //.

When using this symbol, the text written on the

same line in your source code is ignored by

the Preprocessor & Compiler.

For example:

// This will be ignored during the compile. This will not be ignored during the compile.

// This will also ignored during the compile.


CommentsComments

/*

* Programmer: Troy Zinderman

* Date Completed: September 23, 2005

* Class: INSS209

*

* Calculates final grade of students based

* on assignment weights

*

*/

/*

* Programmer: Troy Zinderman

* Date Completed: September 23, 2005

* Class: INSS209

*

* Calculates final grade of students based

* on assignment weights

*

*/Must be included in all

project source code

submissions.





intmain(void){





return (0);}



intmain(void){





return (0);}

2/3/2015

5




/* input - distance in miles. *//* output - distance in kilometers */

/* Get the distance in miles. */

/* Convert the distance to kilometers. */

/* Display the distance in kilometers. */

printf("Enter the distance in miles> ");scanf("%lf", &miles);

kms = KMS_PER_MILE * miles;

printf("That equals %f kilometers.\n", kms);

return (0);}

intmain(void){

double miles, kms;


Main Function


Main FunctionMain Function

Every C program contains a main

function. This marks where the

program execution begins.

A function body is comprised of 2 parts:

Declarations

Executable Statements

Every C program contains a main

function. This marks where the

program execution begins.

A function body is comprised of 2 parts:

Declarations

Executable Statements


Function ComponentsFunction Components

Declarations is the part of a program

that tells the compiler the name of

memory cells in the program.

Executable Statements program lines

that are converted to machine

language instructions and executed by the computer.

Declarations is the part of a program

that tells the compiler the name of

memory cells in the program.

Executable Statements program lines

that are converted to machine

language instructions and executed by the computer.

2/3/2015

6


Function Punctuation & SymbolsFunction Punctuation & Symbols

Functions use punctuation & symbols to identify specific elements or actions inside the code.

Commas (,) separate items in lists

Semicolon (;) identify the end of a statement

Braces ({}) mark the beginning & end of the function

Functions use punctuation & symbols to identify specific elements or actions inside the code.

Commas (,) separate items in lists

Semicolon (;) identify the end of a statement

Braces ({}) mark the beginning & end of the function


Reserved WordsReserved Words

A word that has special meaning in the

C language and can not be used for

any other purpose. Some examples:

Basic coding instructions

if, else, break, switch

Part of declarations

float, int, double

A word that has special meaning in the

C language and can not be used for

any other purpose. Some examples:

Basic coding instructions

if, else, break, switch

Part of declarations

float, int, double


Standard IdentifiersStandard Identifiers

A word that has special meaning but

one that can be redefined by a

programmer (not a good idea).

Common functions from libraries

printf, scanf

A word that has special meaning but

one that can be redefined by a

programmer (not a good idea).

Common functions from libraries

printf, scanf

2/3/2015

7


User-Defined IdentifiersUser-Defined Identifiers

Words that programmers can assign to memory cells to hold data & program results.

User-Defined Identifiers make programmers easier to construct, read, & debug.

There are syntactical rules & recommendations for their use.

Words that programmers can assign to memory cells to hold data & program results.

User-Defined Identifiers make programmers easier to construct, read, & debug.

There are syntactical rules & recommendations for their use.


User-Defined Identifier Rules & Recommendations

User-Defined Identifier Rules & Recommendations

1. An identifier must consist of only letters, digits, & underscores (e.g. ABC_123)

2. An identifier cannot begin with a digit (e.g. 1DIGIT)

3. A C reserved word cannot be used as an identifier (e.g. void)

4. It is recommended that an identifier defined in a C standard library should not be redefined (e.g. printf)

5. It is recommended that an identifier be not longer than 31 characters in length

1. An identifier must consist of only letters, digits, & underscores (e.g. ABC_123)

2. An identifier cannot begin with a digit (e.g. 1DIGIT)

3. A C reserved word cannot be used as an identifier (e.g. void)

4. It is recommended that an identifier defined in a C standard library should not be redefined (e.g. printf)

5. It is recommended that an identifier be not longer than 31 characters in length


Back to Declarations Back to Declarations

Most declarations in a program are for the

assignment of variables.

Variable a name associated with a memory

cell whose value can change.

Variable Declaration a statement that

communicates to the complier the name

of a variable in the program and the kind if

information stored in the variable.

Most declarations in a program are for the

assignment of variables.

Variable a name associated with a memory

cell whose value can change.

Variable Declaration a statement that

communicates to the complier the name

of a variable in the program and the kind if

information stored in the variable.

2/3/2015

8


Variable DeclarationVariable Declaration



Variable Identifier

(Name)

Variable Data TypeComments describing

variable purpose


Data TypesData Types

A set of values and operations that can

be performed on those values

Standard Data Type a data type that is

predefined to the C language.

Enumerated Data Type a data type

that is defined by the programmer

(to be address later in the semester).

A set of values and operations that can

be performed on those values

Standard Data Type a data type that is

predefined to the C language.

Enumerated Data Type a data type

that is defined by the programmer

(to be address later in the semester).


The Integer Data Type (int)The Integer Data Type (int)

An integer is the set of natural numbers (including 0) and their negatives.

The set of integers used inside of a language is limited by the finite size of a memory cell.

The ANSI C standard require that the data type of int must at least include numbers -32767 through 32767.

Examples: -12453, -54, 0, 4325, 32211

An integer is the set of natural numbers (including 0) and their negatives.

The set of integers used inside of a language is limited by the finite size of a memory cell.

The ANSI C standard require that the data type of int must at least include numbers -32767 through 32767.

Examples: -12453, -54, 0, 4325, 32211

2/3/2015

9


The Double Floating-Point Data Type (double)

The Double Floating-Point Data Type (double)

A form used to represent numbers with fractional components.

An abstraction for real numbers since the finite size of a memory cell limits total inclusion.

The ANSI C standard require that the data type of double must at least include numbers 10-37 through 1037.

Examples: 3.14159, 1010.10, 123.0, 1.32e-9

A form used to represent numbers with fractional components.

An abstraction for real numbers since the finite size of a memory cell limits total inclusion.

The ANSI C standard require that the data type of double must at least include numbers 10-37 through 1037.

Examples: 3.14159, 1010.10, 123.0, 1.32e-9


The Character Data Type (char)The Character Data Type (char)

Represents a single character value, to include a letter, a number, or a symbol.

In a C program, character values are enclosed by the apostrophe symbol (single quotes).

However char data type variables should not have them.

Examples: A, 3, *, $, e

Represents a single character value, to include a letter, a number, or a symbol.

In a C program, character values are enclosed by the apostrophe symbol (single quotes).

However char data type variables should not have them.

Examples: A, 3, *, $, e


On to Executable StatementsOn to Executable Statements

Assignment Statement an instruction

that stores a value or a

computational result in a variable.

kms = KMS_PER_MILES * miles;

Assignment Statement an instruction

that stores a value or a

computational result in a variable.

kms = KMS_PER_MILES * miles;

Constant Macro

Variable Identifier

Assignment

Operator (=)

2/3/2015

10


Before & After StatesBefore & After States


Assignment Statements (continued)

Assignment Statements (continued)

sum = sum + item;sum = sum + item;


Executable Statements (continued)

Executable Statements (continued)

Input Operation an instruction that copies data from an input device into memory.

Output Operation an instruction that displays information stored in memory.

In the C language, most of the common input/output functions are supplied in the standard input/output library (stdio.h)

Access to the library is acquired through a pre-processor directive:

#include

Input Operation an instruction that copies data from an input device into memory.

Output Operation an instruction that displays information stored in memory.

In the C language, most of the common input/output functions are supplied in the standard input/output library (stdio.h)

Access to the library is acquired through a pre-processor directive:

#include

2/3/2015

11


The Print Formatted Function (printf)

The Print Formatted Function (printf)

A standard function that allows a

programmer to display a line of

program output.

A program must make a function call to activate the function.

printf(That equals %f kilometers.\n, kms);


programmer to display a line of

program output.

A program must make a function call to activate the function.



printf(That equals %f kilometers.\n, kms);printf(That equals %f kilometers.\n, kms);

printf Function Componentsprintf Function Components

Function Name

Function Argument

Format String




printf Function Componentsprintf Function Components

Print List

Placeholder

2/3/2015

12


Placeholders used in printfPlaceholders used in printf

Placeholder a symbol beginning with a % in a format string that indicates

where to display the output value.

Characters (char data type)

%c

Integers (int data type)

%d

Double Float (double data type)

%f

Placeholder a symbol beginning with a % in a format string that indicates

where to display the output value.


%c


%d


%f


Escape SequencesEscape Sequences

A series of characters used to change

the state of computers and their

attached peripheral devices .

An escape character is used to identify

an alternative interpretation of the next character in the character

sequence.

A series of characters used to change

the state of computers and their

attached peripheral devices .

An escape character is used to identify

an alternative interpretation of the next character in the character

sequence.


Newline Escape SequenceNewline Escape Sequence

A character sequence that is used in a

format string to terminate an output

line.

In the C language, the sequence \n is

typed to terminate a line of output


A character sequence that is used in a

format string to terminate an output

line.

In the C language, the sequence \n is

typed to terminate a line of output


2/3/2015

13


The Scan Format Function (scanf)

The Scan Format Function (scanf)


programmer to capture data from an

input device to be stored into memory.

A program must make a function call to

activate the function.

scanf(%lf, &miles);


programmer to capture data from an

input device to be stored into memory.

A program must make a function call to

activate the function.

scanf(%lf, &miles);


A Note on scanfA Note on scanf

Microsoft has depreciated the use of scanf within newer versions of Visual

Studio. For students using versions above 2010, you will have to switch to using scanf_s or add the following

line as the first preprocessor directive:

#define _CRT_SECURE_NO_WARNINGS

Microsoft has depreciated the use of scanf within newer versions of Visual

Studio. For students using versions above 2010, you will have to switch to using scanf_s or add the following

line as the first preprocessor directive:

#define _CRT_SECURE_NO_WARNINGS


Placeholders used in scanfPlaceholders used in scanf

Uses the same placeholders as printffor characters & integers. Uses a different placeholder for double floats.


%c


%d


%lf

Uses the same placeholders as printffor characters & integers. Uses a different placeholder for double floats.


%c


%d


%lf

2/3/2015

14


scanf(%lf, &miles);scanf(%lf, &miles);scanf(%lf, &miles);

scanf Function Componentsscanf Function Components

VariablePlaceholder

Address-of

operator

scanf(%lf, &miles);


Address-of OperatorAddress-of Operator

A operator (&) that precedes a variable declared in the scanf function. Its

purpose is to store where the data is

stored in memory (not what is stored

in the variable).

A operator (&) that precedes a variable declared in the scanf function. Its

purpose is to store where the data is

stored in memory (not what is stored

in the variable).


Effect of scanfEffect of scanf

2/3/2015

15


How a data line is scannedHow a data line is scanned


The Return StatementThe Return Statement

The return statement transfers control

from a function back to the activator

of the function.

For function main, control is returned to the operating system.

return (0);

The return statement transfers control

from a function back to the activator

of the function.

For function main, control is returned to the operating system.

return (0);


Arithmetic ExpressionsArithmetic Expressions

Operator Meaning

+ Addition

- Subtraction

* Multiplication

/ Division

% Remainder

2/3/2015

16


Evaluation Tree for areaEvaluation Tree for area


Step-by-Step Expression EvaluationStep-by-Step Expression Evaluation


v = (p2 - p1) / (t2 - t1)v = (p2 - p1) / (t2 - t1)

2/3/2015

17


z - (a + b / 2) + w * -yz - (a + b / 2) + w * -y

Copyright 2009 Troy A. Zinderman

Control StructuresControl Structures

Control Structure a combination of individual instructions into a single logical

unit with one entry point and one exit

point.

Compound Statement a group of statements bracketed by { and } that

are executed sequentially.

Control Structure a combination of individual instructions into a single logical

unit with one entry point and one exit

point.

Compound Statement a group of statements bracketed by { and } that

are executed sequentially.

Structured Programming Using Procedural Languages INSS 225 Overview of C


Compound StatementCompound Statement

{statement1;

statement2;

statement3;

.

.

.

.

.

statement n;}

{statement1;

statement2;

statement3;

.

.

.

.

.

statement n;}


2/3/2015

18


ConditionsConditions

Condition an expression that is either false (represented by 0) or true

(represented by 1).

rest_heart_rate > 75

Condition an expression that is either false (represented by 0) or true

(represented by 1).

rest_heart_rate > 75



Relational & Equality Operators

Relational & Equality Operators

Most conditions take one of these forms:

variable relational-operator variable

variable relational-operator constant

variable equality-operator variable

variable equality-operator constant

Most conditions take one of these forms:

variable relational-operator variable

variable relational-operator constant

variable equality-operator variable

variable equality-operator constant



Relational & Equality OperatorsRelational & Equality Operators

Operator Meaning Type

< Less than Relational

> Greater than Relational

= Greater than or equal to

Relational

== Equal to Equality

!= Not equal to Equality


2/3/2015

19


Logical OperatorsLogical Operators

Logical Expression an expression that uses one or more of the logical operators && (and), || (or), ! (not).

n >= 0 && n 5

Logical Expression an expression that uses one or more of the logical operators && (and), || (or), ! (not).

n >= 0 && n 5



Logical ComplementLogical Complement

The complement of a condition has the value 1 (true) when the conditions

value is false; the complement of a

condition has the value of 0 (false) when

the conditions value is nonzero (true).

!(0

2/3/2015

20


Short-Circuit EvaluationShort-Circuit Evaluation

Stopping evaluation of a logical expression as soon as its value can be

determined.

x = 0 y = 6

x > 2 && y > 5

x > 2 || y > 5

Stopping evaluation of a logical expression as soon as its value can be

determined.

x = 0 y = 6

x > 2 && y > 5

x > 2 || y > 5Structured Programming Using Procedural Languages INSS 225 Overview of C


Comparing CharactersComparing Characters

Expression Value

9 >= 0 1 (true)

a < e 1 (true)

B

2/3/2015

21

Copyright 2009 Troy A. ZindermanStructured Programming Using Procedural Languages INSS 225 Selection Structures

SelectionSelection

if statement allows the value of an

expression to select a course of action.

if (rest_heart_rate > 56)

printf(Keep up your exercise program./n);

else

printf(Your heart is in excellent health./n);

if statement allows the value of an

expression to select a course of action.

if (rest_heart_rate > 56)

printf(Keep up your exercise program./n);

else

printf(Your heart is in excellent health./n);


Types of SelectionTypes of Selection

One alternative:

if (condition)

statement;

Two alternatives:

if (condition)

statement;

else

statement;

One alternative:

if (condition)

statement;

Two alternatives:

if (condition)

statement;

else

statement;


Compound Statements within if Statements

Compound Statements within if Statements

if (condition){

statement1;statement1;statement1;

}else{


}

if (condition){


}else{


}

2/3/2015

22


Nested if StatementsNested if Statements

An if statement with another if

statement as its true task or false task.

if (x > 0)

num_pos = num_pos + 1;

else

if (x < 0)

num_neg = num_neg + 1;

else

num_zero = num_zero + 1;


ifs in Sequenceifs in Sequence

if (x > 0)


if (x < 0)


if (x == 0)


if (x > 0)


if (x < 0)


if (x == 0)



Multiple-Alternative Decision FormMultiple-Alternative Decision Form

if (condition)

statement;

else if (condition)

statement;

else if (condition)

statement;

else

statement;

if (condition)

statement;

else if (condition)

statement;

else if (condition)

statement;

else

statement;

2/3/2015

23


The switch StatementThe switch Statement

switch (controlling expression) {label set:

statements;break;

label set:statements;break;


default:statements;

}

switch (controlling expression) {label set:

statements;break;



default:statements;

}


The switch StatementThe switch Statement

switch (watts) {case 25:

life = 2500;break;

case 40:case 60:

life = 1000;break;

case 75:case 100:

life = 750;break;

default:life = 0;

}

switch (watts) {case 25:

life = 2500;break;

case 40:case 60:

life = 1000;break;

case 75:case 100:

life = 750;break;

default:life = 0;

}

Copyright 2009 Troy A. ZindermanStructured Programming Using Procedural Languages INSS 225 Repetition & Loop Statements

Repetition in ProgramsRepetition in Programs

Loop a control structure that repeats a group of steps in a program.

Loop Body the statements that are repeated in the loop body.

Loop a control structure that repeats a group of steps in a program.

Loop Body the statements that are repeated in the loop body.

2/3/2015

24


Kinds of LoopsKinds of Loops

Kind When Used

Counting Loop We can determine before loop execution

exactly how many loop repetitions will be needed to solve the problem

Sentinel- Controlled

Loop

Input of a list of data of any length ended

by a special value

Endfile-Controlled

Loop

Input of a single list of data of any length

from a data file

Input Validation

Loop

Repeated interactive input of a data value

until a value within the range is entered

General Conditional

Loop

Repeated processing of data until a

desired condition is met


Counting LoopsCounting Loops

Counter-controlled loop a loop whose required number of iterations can be determined before loop execution begins.

Set loop control variable to an initial value of zero

While loop control variable < final value

Statement1

Statement2

Statement3

:

Increase loop control variable by 1

Counter-controlled loop a loop whose required number of iterations can be determined before loop execution begins.

Set loop control variable to an initial value of zero

While loop control variable < final value

Statement1

Statement2

Statement3

:

Increase loop control variable by 1


The while StatementThe while Statement

count_emp = 0;

while (count_emp < 7)

{

printf("Hours> ");

scanf("%d", &hours);

printf("Rate> ");

scanf("%lf", &rate);

pay = hours * rate;

printf("Pay is $%6.2f\n", pay);

count_emp = count_emp + 1;

}

printf("\nAll employees processed\n");

count_emp = 0;

while (count_emp < 7)

{

printf("Hours> ");

scanf("%d", &hours);

printf("Rate> ");


pay = hours * rate;

printf("Pay is $%6.2f\n", pay);


}

printf("\nAll employees processed\n");

No Employees

Processed Yet

Testing

Condition

Increment

Control Variable

2/3/2015

25


The Infinite LoopThe Infinite Loop

a loop that executes forever due to an erroneous control condition evaluation or an

erroneous incrementing of the control variable.

while ( 1 != 2 )

a loop that executes forever due to an erroneous control condition evaluation or an

erroneous incrementing of the control variable.

while ( 1 != 2 )


Computing Sums or ProductsComputing Sums or Products

Loops are often used to accumulate a

sum or a product of an unknown

number of inputs.

Accumulator a variable used to store a

value being computed in increments

during the execution of a loop

Loops are often used to accumulate a

sum or a product of an unknown

number of inputs.

Accumulator a variable used to store a

value being computed in increments

during the execution of a loop


Computing Sums or ProductsComputing Sums or Products

total_pay = 0.0;

count_emp = 0;

while (count_emp < number_emp) {

printf("Hours> ");

scanf("%lf", &hours);

printf("Rate > $");


pay = hours * rate;

printf("Pay is $%6.2f\n\n", pay);

total_pay = total_pay + pay;


}

printf("All employees processed\n");

printf("Total payroll is $%8.2f\n", total_pay);

total_pay = 0.0;

count_emp = 0;

while (count_emp < number_emp) {

printf("Hours> ");

scanf("%lf", &hours);

printf("Rate > $");


pay = hours * rate;

printf("Pay is $%6.2f\n\n", pay);

total_pay = total_pay + pay;


}

printf("All employees processed\n");

printf("Total payroll is $%8.2f\n", total_pay);

No Pays

Calculated Yet

Pay Accumulator

Variable

2/3/2015

26


Compound Assignment OperatorsCompound Assignment Operators

An alternate way of writing assignment

operators that combine the mathematic

calculation with the assignment character.

Favored by programmers since it is a more

concise way to write the process.

variable = variable operator expression


variable operator = expression

count_emp += 1;

An alternate way of writing assignment

operators that combine the mathematic

calculation with the assignment character.

Favored by programmers since it is a more

concise way to write the process.

variable = variable operator expression


variable operator = expression

count_emp += 1;


Compound Assignment OperatorsCompound Assignment Operators

time = time - 1;

time -= 1;

total_time = total_time + time;

total_time += time;

product = product * item;

product *= item;

n = n * (x + 1);

n *= x + 1;

time = time - 1;

time -= 1;

total_time = total_time + time;

total_time += time;

product = product * item;

product *= item;

n = n * (x + 1);

n *= x + 1;


The for StatementThe for Statement

an alternate form of loop structure that gives a more concise way to address the 3 portions of loop control.

for (

initialization of the loop control variable,

test of the loop repetition condition,

change (update) of the loop control variable,

)

an alternate form of loop structure that gives a more concise way to address the 3 portions of loop control.

for (

initialization of the loop control variable,

test of the loop repetition condition,

change (update) of the loop control variable,

)

2/3/2015

27


The for StatementThe for Statement

total_pay = 0.0;for (

count_emp = 0; count_emp < number_emp; count_emp += 1

) {

printf("Hours> ");scanf("%lf", &hours);printf("Rate > $");scanf("%lf", &rate);pay = hours * rate;printf("Pay is $%6.2f\n\n", pay);total_pay = total_pay + pay;

}printf("All employees processed\n");printf("Total payroll is $%8.2f\n", total_pay);

total_pay = 0.0;for (

count_emp = 0; count_emp < number_emp; count_emp += 1

) {

printf("Hours> ");scanf("%lf", &hours);printf("Rate > $");scanf("%lf", &rate);pay = hours * rate;printf("Pay is $%6.2f\n\n", pay);total_pay = total_pay + pay;

}printf("All employees processed\n");printf("Total payroll is $%8.2f\n", total_pay);

loop control variable

initialization

loop repetition

condition test

loop control

variable change


Increment & Decrement OperatorsIncrement & Decrement Operators

Operators used to increment or decrement

variables by values of 1.

operator variable

++counter

Side Effect a change in the value of a

variable as a result of carrying out an

operation.

Operators used to increment or decrement

variables by values of 1.

operator variable

++counter

Side Effect a change in the value of a

variable as a result of carrying out an

operation.


Placement of Increment or

Decrement Operators

Placement of Increment or

Decrement Operators

Where the operator is placed upon the variable set the time of Increment or Decrement.

Prefix Increment the expressions value is calculated

(up or down) and then used.

++variable --variable

Postfix Increment the expressions value is used and then calculated (up or down).

variable++ variable--

Where the operator is placed upon the variable set the time of Increment or Decrement.

Prefix Increment the expressions value is calculated

(up or down) and then used.

++variable --variable

Postfix Increment the expressions value is used and then calculated (up or down).

variable++ variable--

Programming Notes

Documents

Transcript of Programming Notes