Problem Solving and Program Design in C (5th Edition) by Jeri R. Hanly and Elliot B. Koffman

Problem Solving and Program Design in C

(5th Edition)

by Jeri R. Hanly and Elliot B. Koffman

CP 202Chapter 3

11-10-1429

© F

CIT

@K

AU

CHAPTER 3 - Outline1. Introduction to Functions

2. Function Header

3. Call Function

4. Function Library

5. Common Errors

2

#

1. Function (noArgument, noReturnValue)

2. The area and the circumference of circle

3. Function (1 Argument, noReturnValue)

4. Function (1 Argument, 1 ReturnValue)

5. Function (noArgument, 1 ReturnValue)

6. Function (2 Arguments, noReturnValue)

7. Performs 3 Square Root Computations

column shows the topics index. column shows the programs index.

© F

CIT

@K

AU

Introduction to FunctionsA. Introduction:

Characteristics: Break the big problem into small problems Each small problem can be solved individually Write a function to solve each of these small problems Some codes to solve the small problems are the same

between the problems, so you can share or reuse these functions again and again

Each function will have a separate memory, so the functions in one program do not share variables

Three terms to remember: Function Header Call Function Function Library

1

-3-

© F

CIT

@K

AU

Functions – Function HeaderA. Introduction:

Each function has to be declared before using it Two ways to declare functions:

1.Declare the function only: similar to declare variables some programmers like to declare a list of functions

first in order to organize the code. Then, they put the body / content of each function later

2.Declare the function with the content: similar to declare and initial variables most of the programmers like to put the body of the

function in the same time in order to save space and time

2

-4-The name of the function should refer to its job

© F

CIT

@K

AU

B1.Syntax (declare the function with the content):

C1.Example:void welcome_msg (void)

{

printf(“Hello World”);

}

return_value function_name(arguments){

function_body}

Functions – Function Header 2

int, double,

char, void

int, double,char, void

Function name: welcome_msgArguments (input): voidReturn (output): void

-5-The name of the function should refer to its job

© F

CIT

@K

AU

B2.Syntax (declare the function only):

C2.Example:void welcome_msg (void);

:

void welcome_msg (void)

{

printf(“Hello World”);

}

return_value function_name(arguments);

Functions – Function Header 2

int, double,

char, void

int, double,

char, void


Declaring functions helps organize the functions’ list

Note: declaring a function only indicates that the body of the function has to be written later

-6-

© F

CIT

@K

AU

Functions – Call FunctionA. Introduction:

Every place in the code you want to use a function, you need to call the function

The function may return a value (int, double, char) or not (void), so there are two ways to call a function

B. Syntax:

C. Example: welcome_msg (); draw_box (2, 3); Kilo = mile_to_kilo (Mile);

3

function_name (arguments);

return_value = function_name (arguments);

-7-

Function name: mile_to_kiloArguments (input): double (Mile)Return (output): double (Kile)


© F

CIT

@K

AU

Functions – Function LibraryA. Introduction:

If a function is written in a different file, you need to #include the file that has the function

The existing functions will help you to write any program faster and better

B. Syntax:

C. Example: #include <stdio.h>

4

#include <file_name>

-8-

The file stdio.h has many functions, such as printf() and scanf()

There are number of libraries existing. Review Table 3.1 from the book

© F

CIT

@K

AU

Function (noArgument,noReturnValue)

A.Problem We need a program that can

draw 2 types of houses under each other

Look at the similarities between the two types, and write one function for this part and other functions for the others parts

Hints: The big house consists of a triangle

and a square The small house consists of a

triangle and a rectangle

Type 1: “Big House”

/\ / \ / \ *------* | | | | *------*

Type 2: “Small House”

/\ / \ / \ *------* | | *------*

-9-

ImplementationProblem Analysis Design

1

Outline Testing Maintenance

© F

CIT

@K

AU


B.Analysis Input Output

Display the following shapes:

Formula

-10-


1


/\ / \ / \ *------* | | | | *------* /\ / \ / \ *------* | | *------*

© F

CIT

@K

AU


C.Design (1st version)1. Display the two houses under each other

-11-


1


/\ / \ / \ *------* | | | | *------* /\ / \ / \ *------* | | *------*

We have to use functions, so look for the similarities

triangle

square

triangle

rectangle

so we can build three functions to draw the two houses

© F

CIT

@K

AU


C.Design (2nd version)1. Build a function called draw_triangle()

receive: voidreturn: void

1.1 Display the following triangle:

2. Build a function called draw_square()receive: voidreturn: void

2.1 Display the following square:

-12-


1


/\ / \ / \

*------* | | | | *------*

exist () means a function not a variable

© F

CIT

@K

AU


C.Design (2nd version)3. Build a function called draw_rectangle()

arguments: voidreturn: void

3.1 Display the following rectangle:

4. Display a big house4.1 Call draw_triangle() 4.2 Call draw_square()

5. Display a small house5.1 Call draw_triangle()5.2 Call draw_rectangle()

-13-


1


*------* | | *------*

You can indicate send/receive variables when you call a function

© F

CIT

@K

AU

Function (noArgument,noReturnValue)#include <stdio.h>

// 1. Build a function called draw_triangle ()void draw_triangle(void){ // 1.1 Display a triangle shape}

// 2. Build a function called draw_square ()void draw_square(void){ // 2.1 Display a square shape}

// 3. Build a function called draw_rectangle ()void draw_rectangle(void){ // 3.1 Display a rectangle shape}

int main(void){ // 4. Display a big house // 4.1 call draw_triangle() // 4.2 call draw_square()

// 5. Display a small house // 5.1 call draw_triangle() // 5.2 call draw_rectangle()

return (0);}

Hint:Put the main() function at the end. Otherwise, you need to do extra steps. You will see an example at the end.

-14-


1


1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.30.31.32.

© F

CIT

@K

AU

Function (noArgument,noReturnValue)1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.

#include <stdio.h>

// 1. Build a function called draw_triangle ()void draw_triangle(void){ // 1.1 Display a triangle shape printf(" /\\ \n"); printf(" / \\ \n"); printf(" / \\ \n");}

// 2. Build a function called draw_square ()void draw_square(void){ // 2.1 Display a square shape printf(" *------* \n"); printf(" | | \n"); printf(" | | \n"); printf(" *------* \n");}

// 3. Build a function called draw_rectangle ()void draw_rectangle(void){ // 3.1 Display a rectangle shape printf(" *------* \n"); printf(" | | \n"); printf(" *------* \n");}

Note: Using \ in the printf() means you have a special symbol, such as \n.If you want to print the symbol \, you need to type it twice.

-15-


1


© F

CIT

@K

AU

Function (noArgument,noReturnValue)30.31.32.33.34.35.36.37.38.39.40.41.42.

int main(void){ // 4. Display a big house draw_triangle(); draw_square();

// 5. Display a small house draw_triangle(); draw_rectangle();

return (0);}

-16-


1


© F

CIT

@K

AU


-17-


1


30.31.32.33.34.35.36.37.38.39.40.41.42.

int main(void){ // 4. Display a big house draw_triangle(); draw_square();

// 5. Display a small house draw_triangle(); draw_rectangle();

return (0);}

© F

CIT

@K

AU

The Area and the Circumference of Circle

A.Problem We need a program to help the users calculate the area

and the circumference for a circle after entering the radius of the circle.

Note: π = 3.14159 area = π × radius2

circumference = 2π × radius

-18-

Circumference Area


2


© F

CIT

@K

AU


B.Analysis Input

PI = 3.14159 radius

Output Area Circumference

Formula Area = PI × radius × radius Circumference = 2 × PI × radius

-19-


2


Area = PI x radius2PIradius Area

Circumference = 2 x PI x radius CircumferencePI

radius

PI has a value unlike radius PI is a constant and not a variable

© F

CIT

@K

AU


C.Design1. Define the constants

PI = 3.14159

2. Get the circle radius radius

3. Calculate the areaarea = PI × radius × radius

4. Calculate the circumferencecircum = 2 × PI × radius

5. Display the area area

6. Display the circumference circum

-20-


2


Also, you can calculate the area then display the

result immediately. Later, you calculate the circumference

and display the result

© F

CIT

@K

AU


-21-


2


Some programs prefer to indicate if a variable is input or output value

© F

CIT

@K

AU


-22-


2


© F

CIT

@K

AU


-23-


2


© F

CIT

@K

AU

Function (1 Argument,noReturnValue)A.Problem

We need a program that helps the users calculate the area and the circumference for a circle after entering the radius of the circle (Similar to Program 2)

The output value of the area has to be inside a box as well as the circumference value. Build a function to draw a box around the value; the header of the function is: void display_box(double value);

-24-


3


Area:*---------*| 78.5397 |*---------*

Circumference:*---------*| 31.4159 |*---------*

© F

CIT

@K

AU

Function (1 Argument,noReturnValue)B.Analysis (Similar to Program 2)

Input PI = 3.14159 radius



-25-


3


The input, output, and the formula of the program did not change

© F

CIT

@K

AU

Function (1 Argument,noReturnValue)C.Design (1st version)

1. Define the constants2. Build a function called display_box() that displays the

argument value in a boxarguments: double (value)return: void

3. Get the circle radius

4. Calculate the area

5. Calculate the circumference

6. Display the area in a box

7. Display the circumference in a box

-26-


3


display_box()double

void

© F

CIT

@K

AU

Function (1 Argument,noReturnValue)C.Design (2nd version)

1. Define the constants: PI = 3.14159

2. Build a function called display_box() that displays the argument value in a box

arguments: double (value)return: void

2.1 Display the value of the argument inside a box value *-------* | value | *-------*

3. Get the circle radius radius

4. Calculate the area:area = PI × radius × radius

-27-


3


1 variable in the display_box(), so 1 variable needs to be declared

© F

CIT

@K

AU

Function (1 Argument,noReturnValue)C.Design (2nd version)

5. Calculate the circumference:circum = 2 × PI × radius

6. Display the area in a box6.1 Display “Area:” on the screen6.2 Call display_box()

send: areareceive: -

7. Display the circumference in a box7.1 Display “Circumference:” on the screen7.2 Call display_box()

send: circumreceive: -

-28-


3


3 variables in the main(), so 3 variables need to be declared

© F

CIT

@K

AU

Function (1 Argument,noReturnValue)

-29-


3


1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.30.31.

#include <stdio.h>

/* 1. Define the constants */#define PI 3.14159

/* 2. a function displays the argument value in a box */void display_box(double value){ /* 2.1 Display the value of the argument inside a box */}

int main(void){ double radius; /* input – radius of a circle */ double area; /* output – area of a circle */ double circum; /* output – circumference */

/* 3. Get the circle radius */

/* 4. Calculate the area */

/* 5. Calculate the circumference */

/* 6. Display the area in a box */ /* 6.1 display “Area:” on the screen */

/* 6.2 call display_box() */

/* 7. Display the circumference in a box */ /* 7.1 display “Circumference:” on the screen */


return(0);}

1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.30.31.32.33.34.35.

© F

CIT

@K

AU


-30-


3


#include <stdio.h>


/* 2. a function displays the argument value in a box */void display_box(double value){ /* 2.1 Display the value of the argument inside a box */ printf("*---------*\n"); printf("| %7.4f |\n“, value); printf("*---------*\n");}


/* 3. Get the circle radius */ printf(“Enter radius> “); scanf(“%lf”, &radius);

1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.

© F

CIT

@K

AU


-31-


3


/* 4. Calculate the area */ area = PI * radius * radius;

/* 5. Calculate the circumference */ circum = 2 * PI * radius;

/* 6. Display the area in a box */ /* 6.1 display “Area:” on the screen */ printf(“Area:\n”); /* 6.2 call display_box */ display_box(area);

/* 7. Display the circumference in a box */ /* 7.1 display “Circumference:” on the screen */ printf(“Circumference:\n”); /* 7.2 call display_box */ display_box (circum);

return(0);}

24.25.26.27.28.29.30.31.32.33.34.35.36.37.38.39.40.41.42.43.44.

© F

CIT

@K

AU


-32-


3






return(0);}

24.25.26.27.28.29.30.31.32.33.34.35.36.37.38.39.40.41.42.43.44.

© F

CIT

@K

AU


-33-


3

Outline

#include <stdio.h>









return(0);}

1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.30.31.32.33.34.35.36.37.38.39.40.41.42.43.44.

radius

(double)

area

(double)

circum

(double)

5.0 78.53975 31.4159

Memory: main()

Output:

X

(double)

31.4159

Memory: display_box() – call 2

X

(double)

78.53975

Memory: display_box() – call 1

Testing Maintenance

© F

CIT

@K

AU

Function (1 Argument,1 ReturnValue)A.Problem

We need a program to help the users calculate the area and the circumference for a circle after entering the radius of the circle (Similar to Program 2)

The output value of the area has to be inside a box as well as the circumference value. Build a function to draw a box around the value; the header of the function is: void display_box(double value); (Similar to Program 3)

Build 2 functions to calculate the area and the circumference; the headers of the functions are: double circle_area(double radius); double circle_circum(double radius);

-34-


4


© F

CIT

@K

AU

Function (1 Argument,1 ReturnValue)B.Analysis (Similar to Program 2)




-35-


4



© F

CIT

@K

AU

Function (1 Argument,1 ReturnValue)C.Design (1st version)



3. Build a function called circle_area() that calculates the area of the circle

arguments: double (radius)return: double (area)

4. Build a function called circle_circum() that calculates the circumference of the circle

arguments: double (radius)return: double (circum)

-36-


4


© F

CIT

@K

AU

Function (1 Argument,1 ReturnValue)C.Design (1st version)





9. Display the circumference in a box

-37-


4


© F

CIT

@K

AU

Function (1 Argument,1 ReturnValue)C.Design (2nd version)







3.1 Calculate the area: area = PI × radius × radius -38-


4


1st way – Tradition way: (step-by-step)• define a new variable• store the result of the equation in

the new variable• return the value of the new

variable

© F

CIT

@K

AU



arguments: double (radius)return: double (2 × PI × radius)

5. Get the circle radius radius6. Calculate the area

6.1 Call circle_area()send: radiusreceive: area

7. Calculate the circumference7.1 Call circle_area()

send: radiusreceive: circum

-39-


4


2nd way: (save space and time)• return the result of the equation

© F

CIT

@K

AU




9. Display the circumference in a box9.1 Display “Circumference:” on the screen

9.2 Call display_box()send: circumreceive: -

-40-


4


© F

CIT

@K

AU

Function (1 Argument,1 ReturnValue)

-41-


4


#include <stdio.h>



/* 3. a function calculates the area of the circle */double circle_area(double radius){ /* 3.1 Calculate the area */}

/* 4. a function calculates the circumference of the circle */double circle_circum(double radius){

}

1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.

© F

CIT

@K

AU


-42-


4



/* 5. Get the circle radius */

/* 6. Calculate the area */ /* 6.1 call circle_area() */

/* 7. Calculate the circumference */ /* 7.1 call circle_circum() */





return(0);}

24.25.26.27.28.29.30.31.32.33.34.35.36.37.38.39.40.41.42.43.44.45.46.47.48.49.

© F

CIT

@K

AU

#include <stdio.h>



/* 3. a function calculates the area of the circle */double circle_area(double radius){ double result; /* 3.1 Calculate the area */ result = PI * radius * radius; return (result);}

/* 4. a function calculates the circumference of the circle */double circle_circum(double radius){ return (2 * PI * radius);}


-43-


4


1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.

1st way – Tradition way: (step-by-step)• define a new variable• store the result of the equation in the new

variable• return the value of the new variable

2nd way: (save space and time)• return the result of the equation

© F

CIT

@K

AU



/* 6. Calculate the area */ /* 6.1 call circle_area() */ area = circle_area(radius);

/* 7. Calculate the circumference */ /* 7.1 call circle_circum() */ circum = circle_circum(radius);


/* 9. Display the circumference in a box */ /* 9.1 display “Circumference:” on the screen */ printf(“Circumference:\n”); /* 9.2 call display_box */ display_box (circum); return(0);}

30.31.32.33.34.35.36.37.38.39.40.41.42.43.44.45.46.47.48.49.50.51.52.53.54.55.56.57.58.59.60.


-44-


4


© F

CIT

@K

AU







30.31.32.33.34.35.36.37.38.39.40.41.42.43.44.45.46.47.48.49.50.51.52.53.54.55.56.57.58.59.60.


-45-


4


© F

CIT

@K

AU


-46-


4

Outline

# include <stdio.h>



/* 3. a function calculates the area of the circle */double circle_area(double radius){ double result; /* 3.1 Calculate the area */ result = PI * radius * radius; return (result);}








1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.30.31.32.33.34.35.36.37.38.39.40.41.42.43.44.45.46.47.48.49.50.51.52.53.54.55.56.57.58.59.60.

radius

(double)

5.0

Memory: circle_circum()

rad

(double)

result

(double)

5.0 78.5397

Memory: circle_area()

X

(double)

31.4159

Memory: display_result() – call 2

X

(double)

78.5397

Memory: display_result() – call 1

radius

(double)

area

(double)

circum

(double)

5.0 78.5397 31.4159

Memory: main()

Output:

Testing Maintenance

© F

CIT

@K

AU

Function (noArgument,1 ReturnValue)A.Problem

We need a program to help the users calculate the area and the circumference for a circle after entering the radius of the circle (Similar to P2)

The output value of the area has to be inside a box as well as the circumference value. Build a function to draw a box around the value; the header of the function is: void display_box(double value); (Similar to P3)

Build 2 functions to calculate the area and the circumference; the headers of the functions are: double circle_area(double radius); double circle_circum(double radius); (Similar to P4)

Build a function to get the radius’ value from the user: double get_radius(void); -47-


5


© F

CIT

@K

AU

Function (noArgument,1 ReturnValue)B.Analysis (Similar to Program 2)




-48-


5



© F

CIT

@K

AU

Function (noArgument,1 ReturnValue)C.Design (1st version)






arguments: double (radius)return: double (circum)

-49-


5


© F

CIT

@K

AU

Function (noArgument,1 ReturnValue)C.Design (1st version)

5. Build a function called get_radius() that gets the value of the radius from the user

arguments: voidreturn: double (radius)





10.Display the circumference in a box

-50-


5


© F

CIT

@K

AU

Function (noArgument,1 ReturnValue)C.Design (2nd version)






arguments: double (radius)return: double (PI × radius × radius)

-51-


5


© F

CIT

@K

AU



arguments: double (radius)return: double (2 × PI × radius)

5. Build a function called get_radius() that gets the value of the radius from the user

arguments: voidreturn: double (radius)

5.1 Get the circle radius radius6. Get the circle radius

6.1 Call get_radius()send: voidreceive: radius

7. Calculate the area7.1 Call circle_area()

send: radiusreceive: area

-52-


5


© F

CIT

@K

AU


8. Calculate the circumference8.1 Call circle_area()

send: radiusreceive: circum



10.Display the circumference in a box10.1 Display “Circumference:” on the screen

10.2 Call display_box() send: circum receive: -

-53-


5


© F

CIT

@K

AU

# include <stdio.h>



/* 3. a function calculates the area of the circle */double circle_area(double radius){

}

/* 4. a function calculates the circumference of the circle */double circle_circum(double radius){

}

/* 5. a function gets the value of the radius from the user */double circle_circum(void){ /* 5.1 Get the circle radius */}

Function (noArgument,1 ReturnValue)

-54-


5


1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.

© F

CIT

@K

AU


/* 6. Get the circle radius */ /* 6.1 call get_radius() */

/* 7. Calculate the area */ /* 7.1 call circle_area() */

/* 8. Calculate the circumference */ /* 8.1 call circle_circum() */





return(0);}


-55-


5


29.30.31.32.33.34.35.36.37.38.39.40.41.42.43.44.45.46.47.48.49.50.51.52.53.54.55.56.

© F

CIT

@K

AU

#include <stdio.h>



/* 3. a function calculates the area of the circle */double circle_area(double radius){ return (PI * radius * radius);}


/* 5. a function gets the value of the radius from the user */double get_radius(void){ double radius; /* 5.1 Get the circle radius */ printf(“Enter radius> “); scanf(“%lf”, &radius); return (radius);}


-56-


5


1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.30.31.32.33.34.35.

© F

CIT

@K

AU


/* 6. Get the circle radius */ /* 6.1 call get_radius() */ radius = get_radius();





36.37.38.39.40.41.42.43.44.45.46.47.48.49.50.51.52.53.54.55.56.57.58.59.60.61.62.63.64.65.66.


-57-


5


© F

CIT

@K

AU


-58-


5



/* 6. Get the circle radius */ /* 6.1 call get_radius() */ radius = get_radius();





36.37.38.39.40.41.42.43.44.45.46.47.48.49.50.51.52.53.54.55.56.57.58.59.60.61.62.63.64.65.66.

© F

CIT

@K

AU

Function (2 Arguments,noReturnValue)

A.Problem We need a program that takes 2 numbers from a

user The two numbers will be sent to a function

called simple_cal() that displays (sum, different, multiplying, and dividing) of the two number

-59-


6


simple_cal()int

voidint

© F

CIT

@K

AU


B.Analysis Input

number 1 number 2

Output the sum of the two numbers the different between the two numbers multiplying of two numbers dividing the two numbers

Formula No need because they are simple operators

-60-


6


© F

CIT

@K

AU


C.Design1. Build a function called simple_cal() that displays the

results of the four simple operators between two numbersarguments: int (num1), int (num2)return: void

1.1 Display the sum of the two numbers num1 + num21.2 Display the different between the two numbers num1 - num21.3 Display multiplying the two numbers num1 * num21.4 Display dividing the two numbers num1 / num2

2. Get the first number from the user number1

3. Get the second number from the user number2

4. Display the results of the four simple operators4.1 Call display_box()

send: number1, number2receive: -

-61-


6


© F

CIT

@K

AU

Function (2 Arguments,noReturnValue)1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.

#include <stdio.h>

/* 1. a function displays the results of the four simple operators */void simple_cal(int num1, int num2){

}

int main(void){ int number1, number2; /* input: the two numbers */

/* 2. Get the first number from the user */

/* 3. Get the second number from the user */

/* 4. Display the results of the four simple operators */

return (0);}

-62-


6


© F

CIT

@K

AU

Function (2 Arguments,noReturnValue)1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.

#include <stdio.h>

/* 1. a function displays the results of the four simple operators */void simple_cal(int num1, int num2){ printf("%d + %d = %d\n", num1, num2, num1+num2); printf("%d - %d = %d\n", num1, num2, num1-num2); printf("%d * %d = %d\n", num1, num2, num1*num2); printf("%d / %d = %d\n", num1, num2, num1/num2);}


/* 2. Get the first number from the user */ printf("Enter Number 1 > "); scanf("%d", &number1);

/* 3. Get the second number from the user */ printf("Enter Number 2 > "); scanf("%d", &number2);

/* 4. Display the results of the four simple operators */ simple_cal(number1, number2);

return (0);}

-63-


6


© F

CIT

@K

AU

Function (2 Arguments,noReturnValue)1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.

#include <stdio.h>

/* 1. a function displays the results of the four simple operators */void simple_cal(int num1, int num2){ printf("%d + %d = %d\n", num1, num2, num1+num2); printf("%d - %d = %d\n", num1, num2, num1-num2); printf("%d * %d = %d\n", num1, num2, num1*num2); printf("%d / %d = %d\n", num1, num2, num1/num2);}


/* 2. Get the first number from the user */ printf("Enter Number 1 > "); scanf("%d", &number1);

/* 3. Get the second number from the user */ printf("Enter Number 2 > "); scanf("%d", &number2);

/* 4. Display the results of the four simple operators */ simple_cal(number1, number2);

return (0);}

-64-


6


© F

CIT

@K

AU

Performs 3 Square Root Computations

A.Problem Write a program that finds the square root of two numbers

and the square root of the sum of the two numbers Note: there is a library called math.h has a

function called sqrt() that receives a value and return the square root of this value. The header of sqrt() is: double sqrt(double);

-65-


7


If you are using an external function, you need to include the library

© F

CIT

@K

AU


B.Analysis Input

number 1 number 2

Output the square root of number 1 the square root of number 2 the square root of (number 1 + number 2)

Formula No need

-66-


7


© F

CIT

@K

AU


C.Design (1st version)1. Get the 1st number from the user

2. Calculate the square root of the 1st number

4. Display the square root of the 1st number

5. Get the second number from the user

6. Calculate the square root of the 2nd number

7. Display the square root of the 2nd number

8. Calculate the square root of the sum of the two numbers

9. Display the square root of the sum

-67-


7


© F

CIT

@K

AU


C.Design (2nd version)1. Include the library math.h in order to use sqrt()

2. Get the 1st number from the user first

3. Calculate the square root of the 1st number3.1 Call sqrt()

send: firstreceive: first_sqrt

4. Display the square root of the 1st number first_sqrt

5. Get the second number from the user second

6. Calculate the square root of the 2nd number6.1 Call sqrt()

send: secondreceive: second_sqrt

7. Display the square root of the 2nd number second_sqrt-68-


7


© F

CIT

@K

AU


C.Design (2nd version)8. Calculate the square root of the sum of the two numbers

8.1 Call sqrt()send: first+secondreceive: sum_sqrt

9. Display the square root of the sum sum_sqrt

-69-


7


© F

CIT

@K

AU

Functions – Common Errors If you placed the main function before the other

functions, you need to declare each of the other functions before the main

-75-

#include <stdio.h>

void simple_cal(int num1, int num2){}

int main(void){ simple_cal(number1, number2);}

#include <stdio.h>

void simple_cal(int num1, int num2); // function declaration

int main(void){ simple_cal(number1, number2);}

void simple_cal(int num1, int num2){}

or

5

© F

CIT

@K

AU

Homework1. Track the memory in Program 5 ?2. Your bank requires you to do some currency

conversions. Write a function that takes the dollars and convert it to riyals then print the result in the main function. (Note: 1 Dollars = 3.75 Riyals)(Apply the Software Development Method to solve this problem)

3. Build a library called math_shapes.h that contains of the 2 functions described in Program 4: 1. circle_area() 2. circle_area()

and re-write the Program 4 by including the new library and removing the 2 functions from the code?(Show the code of the two files and the output in ONE page only)

-76-

…

DON’T forget to display your name and ID in the output

© F

CIT

@K

AU

CHAPTER 3 - Outline1. Introduction to Functions

2. Function Header

3. Call Function

4. Function Library

5. Common Errors

77

#

1. Function (noArgument, noReturnValue)

2. The area and the circumference of circle

3. Function (1 Argument, noReturnValue)

4. Function (1 Argument, 1 ReturnValue)

5. Function (noArgument, 1 ReturnValue)

6. Function (2 Arguments, noReturnValue)

7. Performs 3 Square Root Computations

column shows the topics index. column shows the programs index.

Problem Solving and Program Design in C (5th Edition) by Jeri R. Hanly and Elliot B. Koffman

Documents

Transcript of Problem Solving and Program Design in C (5th Edition) by Jeri R. Hanly and Elliot B. Koffman