2- (Bitwise Operators) (I) Left shifting an unsigned int by 1 bit is equivalent

Question

2- (Bitwise Operators)

(I) Left shifting an unsigned int by 1 bit is equivalent to multiplying the

value by 2. Write a function power2 that takes two integer arguments number and pow and calculates

number * 2pow

Use the shift operator to calculate the result. Print the values as integers and as bits.

(II) What is the output of this C code?

#include <stdio.h>

1. void main()

2. {

3. int a = 5, b = -7, c = 0, d;

4. d = ++a && ++b || ++c;

5. printf(" %d%d%d%d", a, b, c, d);

6. }

a) 6 -6 0 0

b) 6 -5 0 1

c) -6 -6 0 1

d) 6 -6 0 1

(III) What is the output of this C code?

1. #include <stdio.h>

2. int main()

3. {

4. int x = 2;

5. int y = -4

6. x = x << 1;

7. y = y >> 1;

8. printf("%d %d ", x, y);

9. }

a) 4 -2

b) 1 -8

c) Depends on the compiler

d) Compiler error

Explanation / Answer

-- Code

#include <stdio.h>
void power2(int number, int p)
{
int i;
printf("Given - %d - ",number);
printBinary(number);
  
// this part shifts the number to left by 1 and it does for p times
for(i=0;i<p;i++)
{
number = number << 1;
}
printf(" After shifting - %d - ",number);
printBinary(number);
}

// this is for printing binary number, used recursion
void printBinary(int n)
{
if(n>0)
{
printBinary(n/2);
printf("%d",n%2);
}
}

int main()
{
power2(10,3); // calls power2 to shift 10 thrice
}

-- Sample Output

Given - 10 - 1010

After shifting - 80 - 1010000

[II]

c) -6 -6 0 1

[III]

d) Compiler error

It shows compiler error because 5th line is not ending with ;

If that is a typo, answer will be a) 4 -2

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