How To Find The Leading Number Of Zero's In a Number using C

Question

for example,if i have number 64,then its binary representation would be 0000 0000 0000 0000 0000 0000 0100 0000 so leading number of zero\'s is 25. remember i have to calculate

Answer 1

Right shift is your friend.

    int input = 64;
    int sample = ( input < 0 ) ? 0 : input;
    int leadingZeros = ( input < 0 ) ? 0 : 32;

    while(sample) {
        sample >>= 1;
        --leadingZeros;
    }
    printf("Input = %d, leading zeroes = %d\n",input, leadingZeros);