Bitwise Operations

As Embedded C is an extension of C Language. It inherits all the fundamental operators of C. In C there are 6 bitwise operators. These operators Operate on Binary Level on the data can be seen in the below table :

Bitwise Operations Embedded C Interview Questions :

Q1: Write a program to select the 4th bit from an integer value 'x' using a bit mask and the bitwise AND operator.
Ans:

#include 

int main() 
{
    int x = 0b10101110;  /* binary representation of 174 */
    
    /* Select the 4th bit using a bit mask and the bitwise AND operator */
    int bit4 = (x & (1 << 3)) >> 3;
    
    printf("The 4th bit of x is %d\n", bit4); /* should print 1 */
    
    return 0;
}

Q2: Write a program to clears the 2nd bit from an integer value 'x' using a bit mask and the bitwise AND operator.
Ans:

#include 

int main() 
{
    int x = 0b11011101;  /* binary representation of 221 */
    
    /* Clear the 2nd bit using a bit mask and the bitwise AND operator */
    x &= ~(1 << 1);
    
    printf("x after clearing the 2nd bit: %d\n", x);  /* should print 219 (0b11011011) */
    
    return 0;
}

Q3: Write a program to set the 3rd bit of an integer value 'x' using a bit mask and the bitwise OR operator.
Ans:

#include 

int main() 
{
    int x = 0b01101001;  /* binary representation of 105 */
    
    /* Set the 3rd bit using a bit mask and the bitwise OR operator */
    x |= (1 << 2);
    
    printf("x after setting the 3rd bit: %d\n", x);  /* should print 109 (0b01101101) */
    
    return 0;
}

Q4: Write a program to set the nth bit of a given integer to 1.
Ans:

#include 

int main() 
{
    int num, n;
    printf("Enter a number: ");
    scanf("%d", &num);
    printf("Enter the bit position to set: ");
    scanf("%d", &n);
    num |= (1 << n);
    printf("The new number is: %d", num);
    return 0;
}

Q5: Write a program to toggle the nth bit of a given integer.
Ans:

#include 

int main() 
{
    int num, n;
    printf("Enter a number: ");
    scanf("%d", &num);
    printf("Enter the bit position to toggle: ");
    scanf("%d", &n);
    num ^= (1 << n);
    printf("The new number is: %d", num);
    return 0;
}

Q6: Write a program to count the number of set bits in a given integer.
Ans: 

#include 

int main() 
{
    int num, count = 0;
    printf("Enter a number: ");
    scanf("%d", &num);
    while (num != 0) 
    {
        if (num & 1) 
        {
            count++;
        }
        num >>= 1;
    }
    printf("The number of set bits is: %d", count);
    return 0;
}

Q7: Write a program to count the number of zeroes in a given integer using bitwise operator.
Ans:

#include 

int main() 
{
    int num, count = 0;
    printf("Enter a number: ");
    scanf("%d", &num);
    while (num != 0) 
    {
        if ((num & 1) == 0) 
        {
            count++;
        }
        num >>= 1;
    }
    printf("The number of zero bits is: %d", count);
    return 0;
}

Q8: Write a program to multiply an integer value 'x' by 2 using left shift operator.
Ans: 

#include 

int main() 
{
    int x = 10;
    
    /* Multiply x by 2 using left shift */
    x = x << 1;
    
    printf("x after left shift: %d\n", x);  /* should print 20 */
    
    return 0;
}

Q9: Write a program to check if the nth bit of a given integer is set or not.
Ans: 

#include 

int main() 
{
    int num, n;
    printf("Enter a number: ");
    scanf("%d", &num);
    printf("Enter the bit position to check: ");
    scanf("%d", &n);
    if ((num >> n) & 1) 
    {
        printf("The bit is set.\n");
    } 
    else 
    {
        printf("The bit is not set.\n");
    }
    return 0;
}

Q10: Write a program to divide an integer value 'x' by 2 using right shift operator.
Ans: 

#include 

int main() 
{
    int x = 10;
    
    /* Divide x by 2 using right shift */
    x = x >> 1;
    
    printf("x after right shift: %d\n", x);  /* should print 5 */
    
    return 0;
}

Q11: Write a program to swap two values of integer variables using XOR operator. 
Ans:

#include 

int main() 
{
    int x = 10;
    int y = 20;
    
    /* Swap x and y using XOR */
    x = x ^ y;
    y = x ^ y;
    x = x ^ y;
    
    printf("x after XOR swap: %d\n", x);  /* should print 20 */
    printf("y after XOR swap: %d\n", y);  /* should print 10 */
    
    return 0;
}