Extract and Modify Field in a 32-bit Register

Code

#include <stdio.h>
#include <stdint.h>

uint32_t update_register(uint32_t reg) 
{
    int num=0;
    for(int i=10,j=0;i<=14;i++,j++)
    {
        if((reg>>i)&1==1)
            num |=1<<j;
        else
            num &=~(1<<j);
    }
    if(num<31)
    {
        num++;
        int mask=(1<<5)-1;
        reg &=~(mask<<10);
        reg |=(num & mask)<<10;
        return reg;
    }
    else if(num>=31)
    {
        return reg;
    }
}

int main() {
    uint32_t reg;
    scanf("%u", &reg);
    uint32_t updated = update_register(reg);
    printf("%u", updated);
    return 0;
}

Solving Approach