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Computer Programming andComputer Programming and

Problem SolvingProblem Solving

LectureLecture -- 33

P.THENDRALP.THENDRALAssist.Prof.SeniorAssist.Prof.Senior

SCSESCSE

SJT 511SJT 511 26A26Athendral.p@vit.ac.inthendral.p@vit.ac.in

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Input UsingInput Using ScanfScanf The scanf() function is the output method

The scanf format stringholds placeholder orformat specifierrepresenting the type of valuethat will be entered by the user.

These placeholders are exactly the same as theprintf() function like %d for integerss, %f forfloats, and %lf for long doubles.

The scanf() function requires the memoryaddress of the variable to which we want to savethe input value

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UsingUsing scanfscanf() function() function#include

int main(void){

int a;

printf("Please input an integer value: ");scanf("%d", &a);}

"Read in an integer from the user and store it atthe address of variable a".

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scanfscanf() uses & operator() uses & operator scanfscanf() uses() uses

&& -- Address of OperatorAddress of Operator

scanf(scanf(%d%d%d%d%d%d,&a,&b,&c,&a,&b,&c););

&a&a -- address of variable aaddress of variable a

&b&b -- address of variable baddress of variable b

&c&c -- address of variable caddress of variable c

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ExpressionsExpressions

ANDANDOperatorsOperators

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ExpressionsExpressions

An expressionis a combination of constants,variables, and operators that are used to denotecomputations.

For instance, the following:

(2 + 3) * 10 is an expression that adds 2 and

3 first, and then multiplies the result of theaddition by 10. (The final result of the expressionis 50.)

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ExpressionsExpressions

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Assignment OperatorAssignment Operator The = operator is called an assignment operator

The general statement form to use an assignment operatoris left-hand-operand = right-hand-operand;

The value of the right-hand-operand to be assigned (orwritten) to the memory location of the left-hand-operand.Thus, after the assignment, left-hand-operand will be equalto the value of right-hand-operand.

For example, the statement a = 5; writes the value of theright-hand operand (5) into the memory location of the

integer variable a (which is the left-hand operand in thiscase).

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Assignment OperatorAssignment Operator Similarly, the statement b = a = 5; assigns 5 to

the integer variable a first, and then to theinteger variable b. After the execution of thestatement, both a and b contain the value of 5.

An expression such as 6 = a, is actually

backwards and will not work.

The = operator always works from right toleft; therefore the value on the left must be

some form of a variable that can receive the datafrom the expression on the right.

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Arithmetic OperatorsArithmetic Operators

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Precedence Rule in ArithmeticPrecedence Rule in Arithmetic

OperatorOperator

Multiplication, Division and RemainderMultiplication, Division and Remainder

operators have higher precedence thanoperators have higher precedence thanthe addition and subtraction operatorsthe addition and subtraction operators

5 + 3 * 2 will be giving the result 11 not5 + 3 * 2 will be giving the result 11 not

1010

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Arithmetic ExpressionsArithmetic Expressions

Uses Arithmetic operatorsUses Arithmetic operators

Order of Evaluation from Left to RightOrder of Evaluation from Left to Right

Follows Precedence Rules of theFollows Precedence Rules of the

arithmetic operatorsarithmetic operators

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Arithmetic Assignment OperatorsArithmetic Assignment Operators