不想用if的进来

第一种：

#include <bits/stdc++.h>
using namespace std;

int main(){

    int day;
    cin >> day;
	if (day >= 8 || day <= 0){
		cout << "no";
		return 0;
	}
	
	string a[] = {"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"};
	cout << a[day - 1];
    
    return 0;
}

第二种：

#include <bits/stdc++.h>
using namespace std;

int main(){

    int day;
    cin >> day;

    switch(day){
        case 1:
            cout << "Monday";
            break;
        case 2:
            cout << "Tuesday";
    		break;
    	case 3:
    		cout << "Wednesday";
    		break;
    	case 4:
    		cout << "Thursday";
    		break;
    	case 5:
    		cout << "Friday";
    		break;
    	case 6:
    		cout << "Saturday";
    		break;
    	case 7:
    		cout << "Sunday";
    		break;
    	default:
    		cout << "no";
    		break;
    }
    
    return 0;
}