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#include <iostream>
#include <cmath>
using namespace std;
int main()
{
cout << "Input a number: ";
int m;
cin >> m;
double sqrtm=sqrt(m*1.0);
if(m%2 == 0) //如果是偶数,声明不是素数并退出
cout << m << " isn't a prime." << endl;
else
{
for(int i=1; i<=sqrtm; i++) //除以奇数,能除尽则声明是素数并退出,否则继续循环直到结束
{
if(m%(2*i+1) == 0)
{
cout << m << " isn't a prime." << endl;
return -1;
}
}
cout << m << " is a prime." << endl;
}
return 0;
}
#include <iostream>
#include <cmath>
using namespace std;
int main()
{
cout << "Input a number: ";
int m;
cin >> m;
double sqrtm=sqrt(m*1.0);
if(m%2 == 0) //如果是偶数,声明不是素数并退出
cout << m << " isn't a prime." << endl;
else
{
for(int i=3; i<=sqrtm; i+=2) //除以奇数,能除尽则声明是素数并退出,否则继续循环直到结束
{
if(m%i == 0)
{
cout << m << " isn't a prime." << endl;
return -1;
}
}
cout << m << " is a prime." << endl;
}
return 0;
}