第一反应：if 秒了；

第二反应：嗯？好像秒不了；

第三反应：if + bool 秒了。

上代码：

#include <bits/stdc++.h>
using namespace std;
int x;
bool b;
int main() {
	cin >> x;
	if (x % 3 == 0) {
		cout << "3 ";
		b = 1;
	} if (x % 5 == 0) {
		cout << "5 ";
		b = 1;
	} if (x % 7 == 0) {
		cout << "7 ";
		b = 1;
	} if (b == 0) cout << 'n';
	return 0;
}

#include<bits/stdc++.h> using namespace std; int main() { int x; cin>>x; if(x%30 && x%50 && x%70) { cout<<3<<" "<<5<<" "<<7<<endl; exit(0); } else if(x%150 || x%210 || x%350) { if(x%150) { cout<<3<<" "<<5<<endl; exit(0); } if(x%210) { cout<<3<<" "<<7<<endl; exit(0); } if(x%350) { cout<<5<<" "<<7<<endl; exit(0); } } else if(x%30 || x%50 || x%70) { if(x%30) { cout<<3<<endl; exit(0); } if(x%50) { cout<<5<<endl; exit(0); } if(x%7==0) { cout<<7<<endl; exit(0); } } else { cout<<"n"<<endl; } return 0; } 如有大冤种看到，请自主换行。

#include <bits/stdc++.h> using namespace std; int x; bool b; int main() { cin >> x;

if (x % 3 == 0) {
	cout << "3 ";
	b = 1;
} if (x % 5 == 0) {
	cout << "5 ";
	b = 1;
} if (x % 7 == 0) {
	cout << "7 ";
	b = 1;
} if (b == 0) cout << 'n';
return 0;

}

#include<bits/stdc++.h> using namespace std; int main(){ int a,b,c,d; cin>>a; b=a%3; c=a%5; d=a%7; if (b0 and c0 and d0) {cout<<3<<" "<<5<<" "<<7;} else if (b0 and c0) {cout<<3<<" "<<5;} else if (b0 and d0) {cout<<3<<" "<<7;} else if (d0 and c0) {cout<<5<<" "<<7;} else if (b0) {cout<<3;} else if (c0) {cout<<5;} else if (d0) {cout<<7;} else {cout<<"n";} return 0; } //自己换行