C Operators Pro

Check if a given Integer is Power of 2 using Bitwise Operators

#include

#include

#define num_bits_int (8*sizeof(int))

int power_of_2(unsigned int);

int main()

{

            unsigned int num;

            printf("\nEnter Number");

            scanf("%d", &num);

    power_of_2(num);

}

int power_of_2(unsigned int x)

{

    int i, count = 0, result, shift_num;

    for (i = 0;i <= Num_bits_int;i++)

    {

        shift_num = x >> i;

        result = shift_num & 1;

        if (res == 1)

            count++;

    }

    if (count % 2 == 1)

        printf("Yes");

    else

        printf("No");

        getch();

}

Output

Enter Number128

Yes

Enter Number126

No

Swap two Integers without using Temporary Variables and Bitwise Operations

#include 

#include 

void swap(int *, int *);

void main()

{

    int x, y;

    printf("Enter 2 nos: \n");

    scanf("%d %d", &x, &y);

    printf("\nYou have entered x = %d y = %d \n", x, y);

    swap(&x,&y);    // passing the 2 nos to the swap function

}

void swap(int *a, int *b)

{

    *a = *a + *b;

    *b = *a - *b;

    *a = *a - *b;

    printf("Swapped . . . .\n"); 

    printf("x = %d y = %d\n", *a, *b); 

    getch();

}

Output

Enter 2 nos:

4

7

You have entered x=4 y=7

Swapped . . . .

x=7 y=4

Replace Bits in Integer x from Bit Position a to b from another Integer y

#include 

#include 

void changebits(int, int, int, int);

int main()

{

    int num1, num2, pos1, pos2;

    clrscr();

    printf("**Replacing the bits in integer x from bit position a to b from another integer y**\n");

    printf("read number 1\n");

    scanf("%x", &num1);

    printf("Read number 2:\n");

    scanf("%x", &num2);

    printf("Read LSB postion:\n");

    scanf("%d", &pos1);

    printf("MSB should always be greater than LSB\n");

    printf("Read MSB position:\n");

    scanf("%d", &pos2);

    changebits(num1, num2, pos1, pos2);

    return 0;

}

void changebits(int num1, int num2, int pos1, int pos2)

{

    int temp1, temp_1, buffer2, bit1 = 0, bit2 = 0, counter = 0, a = 1;

    temp1 = num1;

    temp_1 = num1;

    buffer2 = num2;

    for (;pos1 <= pos2;pos1++)        

    {

        a = 1;

        num1 = temp_1;

        num2 = buffer2;

        while (counter <= pos1)

        {

            if (counter  == pos1)        

                bit1 = (num1&1);    

            counter++;

            num1>> = 1;

        }

        counter = 0;

        while (counter <= pos1)

        {

            if (counter == pos1)

                bit2 = (num2&1);        

            counter++;

            num2 >>= 1;

        }

        counter = 0;

        if (bit1 == bit2);

        else

        {

            while (counter++<pos1)

                a = a << 1;                

            temp1 ^= a;    

        }

        counter = 0;

    }

    printf("the number num1 after shifting the bits is 0x%x\n", temp1); 

getch();

}

Output

read number 1

0x11223344

Read number 2:

0x55667788

Read LSB postion:

12

MSB should always be greater than LSB

Read MSB position:

19

The number num1 after shifting the bits is 0x11267344