有一个长方体，长宽高分别用a,b,c来表示，正面面积加上面面积之和等于209，且长宽高都是素数，求出所有满足的长宽高。


#include<stdio.h>
#include <math.h>
int f(int x);
void main()
{
    int a,b,c,x=1;
    for(a=2;a<=52;a++)
        for(b=2;b<=102;b++)
            for(c=2;c<=102;c++)
            {
                if(a*b+a*c==209)
                {
                           
                        
                                
                        if( f(a)&&f(b)&&f(c) )        
                        printf("a=%d,b=%d,c=%d\n",a,b,c);
                                       
                }
            }
}

int f(int x)
{
    int n;
    for(n=2;n<=sqrt(x);n++)                    //想了半天终于想通是没加等号的问题(sqrt前面那个等号)
        if(x%n==0)
        {
            return 0;
            break;
        }
    return 1;
}