为什么我没有正确的ro答案？

#include<stdio.h>
#include <math.h>
int main()
{
    float pb;
    float N;
    float ro;
    float nb;
    printf(" Now we will find the number of charges and users n n n ");
    printf(" Please enter the probability n ");
    printf(" The probability is ");
    scanf("%f",&pb);

    printf("n n Please enter the number of circuits N n");
    printf("The number is");
    scanf("%f",&N);
    while ( pb>0.01 )
    {
        pb=1/(1+N/(ro*pb));
        ro=ro+0.01;
    }
    printf("%f",ro);
}