题面
Given a function isPrime to test if an integer n is a prime number or not.
Write a program to input an integer n, and to output:
-- “Is a prime number” if n is a prime number
-- or “Is NOT a prime number” if n is a not a prime number.
输入格式
input an integer n
输出格式
output:
-- “Is a prime number” if n is a prime number
-- or “Is NOT a prime number” if n is a not a prime number.
样例
输入
2
输出
Is a prime number
输入
10
输出
Is NOT a prime number
输入
57
输出
Is NOT a prime number
提示
#define TRUE 1
#define FALSE 0
int isPrime(int n)
{ int i;
if (n <= 1) return FALSE;
if (n == 2) return TRUE;
if (n % 2 == 0) return FALSE;
for (i = 3; i <= sqrt (n)+1; i += 2)
{ if (n % i == 0) return FALSE; }
return TRUE;
}