Question

How to find the position of MSB bit of an unsigned integer number in C

Answer 1

#include <stdio.h>

int GetMsbPos(unsigned int num) {
    int pos = 0;

    while (num) {
        pos++;
        num = num >> 1;
    }

    return pos - 1;
}

int main()
{
    unsigned int num = 127; // 01111111
    printf("Position of MSB bit of %d is: %d\n", num, GetMsbPos(num));
    
    num = 3; // 0011
    printf("Position of MSB bit of %d is: %d\n", num, GetMsbPos(num));

    return 0;
}

  
  
  
/*
run:
  
Position of MSB bit of 127 is: 6
Position of MSB bit of 3 is: 1
  
*/

 

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