Right and Wrong Outputs.Language C

[jinendrarocks]

I wrote a program to check the max no. of consecutive 1s in binary form of given decimal no. but sometimes it is given wrong output.
For example if I enter 439 I get 4 as output but correct output is 3.

............... .......c

#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>

int main(){
    int n,max=0,count=0; 
    scanf("%d",&n);
    
    while(n!=0)
    {
        if(n%2!=0)
         {   
            count++;
        }
        
        else
         {
            if(max<count)
           { 
                max=count;
                count=0;
            }
        }
        n/=2;
    }
    if(count>max)
        max=count;
    
    printf("%d",max);
    return 0;
}

............... .........

[weaknessforcats]

I suggest you not use n /= 2. This makes n a new number with its own binary representation.

Instead make n an unsigned int to avoid int formatting (like 2's complement for negative numbers).

Then compare each bit individually:

n & 1

which will be true if the right bit of n is a 1 and false otherwise.

Then shift the bits in n to the right by 1 position

n >> 1

then when you n & 1 you are testing the second bit in the original n.

Continue in this manner until you have shfted n right by the number of bits in your unsigned int.

[donbock]

Shift right until the result is zero -- that way you don't have to know how many bits are in an unsigned int.