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C program to round off an integer number to the next lower multiple of 2

Here, we are going to learn how to round off an integer number to the next lower multiple of 2 in C programming language?
Submitted by Nidhi, on July 24, 2021

Problem Solution:

Read an integer number from the user, and then we will round off the input number to the next lower multiple of 2 using C program.

Program:

The source code to round off an integer number to the next lower multiple of 2 is given below. The given program is compiled and executed using GCC compile on UBUNTU 18.04 OS successfully.

// C program to round off an integer number
// to the next lower multiple of 2

#include <stdio.h>

int main()
{
    int tmp = 1;
    int num = 0;
    int i = 0;

    printf("Enter number: ");
    scanf("%d", &num);

    if (num > 0) {
        for (; tmp <= num >> 1;)
            tmp = tmp << 1;
        num = tmp;
    }
    else {
        num = ~num;
        num = num + 1;

        for (; tmp <= num >> 1;)
            tmp = tmp << 1;

        tmp = tmp << 1;
        tmp = ~tmp;
        tmp = tmp + 1;
        num = tmp;
    }
    printf("Result is: %d\n", num);

    return 0;
}

Output:

RUN 1:
Enter number: 6
Result is: 4

RUN 2:
Enter number: 34
Result is: 32

RUN 3:
Enter number: 732
Result is: 512

Explanation:

In the main() function, we read an integer number from the user and then we round off the given integer number to the next lower multiple of 2 and printed the result on the console screen.