Computer system

Multiple increment operators inside printf
#include<stdio.h>
void main() {
int i = 1;
printf("%d %d %d", i, ++i, i++);
}
Output : 3 3 1



Pictorial representation




Explanation of program

I am sure you will get confused after viewing the above image and output of program.
1. Whenever more than one format specifiers (i.e %d) are directly or indirectly related with
same variable (i,i++,++i) then we need to evaluate each individual expression from right
to left.
2. As shown in the above image evaluation sequence of expressions written inside printf
will be – i++,++i,i
3. After execution we need to replace the output of expression at appropriate place
No Step Explanation

Evaluate
1 At the time of execution we will be using older value of i = 1
i++

Evaluate At the time of execution we will be increment value already modified after
2
++i step 1 i.e i = 3

2 Evaluate i At the time of execution we will be using value of i modified in step 2




C PROGRAMMING Page 40

,Postfix and Prefix Expression in Same Statement
#include<stdio.h>
#include<conio.h>
void main() {
int i = 0, j = 0;
j = i++ + ++i;
printf("%d\n", i);
printf("%d\n", j);
}

Output :
2
2

Explanation of Program




Conditional Operator/ Ternary operator:
conditional operator checks the condition and executes the statement depending of the condition.
A conditional operator is a ternary operator, that is, it works on 3 operands.
Conditional operator consist of two symbols.

1 : question mark (?).
2 : colon ( : ).


C PROGRAMMING Page 41

, Syntax : condition ? exp1 : exp2;

It first evaluate the condition, if it is true (non-zero) then the “exp1” is
evaluated, if the condition is false (zero) then the “exp2” is evaluated.

#include <stdio.h>
int main(){
char February;
int days;
printf("If this year is leap year, enter 1. If not enter any integer: ");
scanf("%c",&February);
// If test condition (February == 'l') is true, days equal to 29.
// If test condition (February =='l') is false, days equal to 28.
days = (February == '1') ? 29 : 28;
printf("Number of days in February = %d",days);
return 0;
}

Output
If this year is leap year, enter 1. If not enter any integer: 1
Number of days in February = 29


Bitwise Operators:
Bitwise operators are used to manipulate the data at bit level. It operates on integers only. It
may not be applied to float.In arithmetic-logic unit (which is within the CPU), mathematical
operations like: addition, subtraction, multiplication and division are done in bit-level which
makes processing faster and saves power. To perform bit-level operations in C programming,
bitwise operators are used.

Operator Meaning
& Bitwise AND
| Bitwise OR
^ Bitwise XOR
<< Shift left
>> Shift right
~ One‟s complement.


Bitwise AND operator &
The output of bitwise AND is 1 if the corresponding bits of two operands is 1. If either bit of an
operand is 0, the result of corresponding bit is evaluated to 0.
Let us suppose the bitwise AND operation of two integers 12 and 25.
12 = 00001100 (In Binary)
25 = 00011001 (In Binary)
C PROGRAMMING Page 42