```
#include "conio.h"
#include "stdio.h"
#include "math.h"
int isPrime(int n)
{
int i,isTrue=1;
for(i=2; i<(int)sqrt(n); i++)
if(n%i==0)
return 0;
else return 1;
}
int main()
{
int N;
printf("Enter n: ");
scanf("%d",&N);
if(isPrime(N))
printf("prime");
else
printf("Not prime\n");
getch();
return 0;
}
```

here is my source code, but when i test , sometimes it's true sometimes it's false. I don't know what is my mistake

Please help me solve it

Thanks a lot!