分析:不能被 2~sqrt(m) 之间任何数整除。
include <stdio.h>
int main(void)
{
int m, i, k ;
printf("input number:") ;
scanf("%d", &m) ;
k = sqrt(m) ;
for (i = 2; i <= k; ++i)
if (m % i == 0)
break ;
if (i >= k + 1)
printf("%d is a prime number.", m) ;
else
printf("%d is not a prime number.", m) ;
return 0 ;
}
int main(void)
{
int m, i, k ;
printf("input number:") ;
scanf("%d", &m) ;
k = sqrt(m) ;
for (i = 2; i <= k; ++i)
if (m % i == 0)
break ;
if (i >= k + 1)
printf("%d is a prime number.", m) ;
else
printf("%d is not a prime number.", m) ;
return 0 ;
}