Question

我试图在下面做出如下声明。如果年龄大于20且小于50，继续。如果年龄小于20且大于50，则重新启动错误。如果有的话，错误，重启。

但是，出于某种原因，如果有条件，它会直接跳过其他地方并直接转向其他地方。如果我输入＆＃34; 19＆＃34;对于年龄，它输出＆＃34;错误。＆＃34;，如果我输入51年龄，它输出＆＃34;错误。＆＃34;怎么了？

#include "stdafx.h"
#include <iostream>
#include <string>
using namespace std;


int plyAgeCreate() {

    int plyAge = 0;

    cout << "Enter an age" << endl;
    cin >> plyAge;

    //If age is greator than 20 and less than 50, accept.
    //Else if age is less than 20 but greator than 50, decline.
    //else, error. Restart.

    if (plyAge >= 20 && plyAge <= 50) {
        cout << "Welcome!" << endl;
    }
    else if (plyAge < 20 && plyAge > 50) { //Why is this being skipped?
        cout << "Between 20 and 50" << endl;
        return plyAgeCreate();
    }
    else {
        cout << "Error" << endl;
        return plyAgeCreate();
    }



}


int main()
{

    plyAgeCreate();

    system("pause");
    return 0;
}

Answer 1

错误的逻辑：

否则if（plyAge＆lt; 20＆amp;＆amp; plyAge＆gt; 50）//这种情况永远不会成真

应该是

else if (plyAge < 20 || plyAge > 50)

Answer 2

使用或，而不是和。如果数字小于20且超过50，它只会进入那里，这是不可能的。如果是19，则必须更改为51，或者将其更改为此或删除它。

else if (plyAge < 20 || plyAge > 50) { //Why is this being skipped?

Answer 3

试试这个。

#include "stdafx.h"
#include <iostream>
#include <string>
using namespace std;


int plyAgeCreate() {

    int plyAge = 0;

    cout << "Enter an age" << endl;
    cin >> plyAge;

    //If age is greator than 20 and less than 50, accept.
    //Else if age is less than 20 but greator than 50, decline.
    //else, error. Restart.

    if (plyAge >= 20 && plyAge <= 50) {
        // This means Age is Between 20 and 50
    }
    else { 
       //This means age is below 20 OR above 50
    }    
    // There cannot another case. Either between 20 - 50 or not between 20 - 50
}


int main()
{

    plyAgeCreate();

    system("pause");
    return 0;
}

如果声明跳过其他，如果直接到其他

3 个答案: