在C语言中使用“ pow（）”时非法使用浮点错误

Question

I am getting "Illegal use of floating point" error in line no 8,10 and 12.

#include<stdio.h>
#include<conio.h>
#include<math.h>
void main()
{   int p,i,c=0;
    scanf("%d",&p);
    for(i=11;i>=0;i--)
    {   if((p==pow(2,i))&&(p%pow(2,i)==0))      //here
            c++;
        else if((p/pow(2,i)!=0)&&(p%pow(2,i)!=0))   //here
        {       c++;
            p=p%pow(2,i);               //here
        }
    }
    printf("%d",c);
    getch();
}

I think there is a problem while calculating the remainder of p using the pow() funciton. Please help me.

Answer 1

You cannot use a float or double value for modulo ( % ). The value for modulo needs to be an integer, which is what your compiler is telling you about when it gives you the error "Illegal use of floating point"

You are not supposed to use the modulo operator for anything else then

<integer value>%<integer value>

If you just want to evaluate your double as if it was an int (without rounding), then you can just cast the double to int .

Like this:

p%(int)(pow(2,i))!=0