如何在 switch 语句中选择一系列值?

How do I select a range of values in a switch statement?(如何在 switch 语句中选择一系列值?)

问题描述

当我尝试编译时出现此错误:

代码:

#include <iostream>使用命名空间标准；诠释主要(){积分；//Vraag de scorecout <<分数:";cin>>分数;//转变开关(分数){案例>= 100:cout <<一个";休息;案例>= 50:cout <<乙"；休息;案例>= 25:cout <

我该如何解决这个问题?这是一个控制台应用程序，Win32，我的 IDE 是 Windows Enterprise C++ 2010.

我正在学习从游戏编程开始 C++.

在 C++ 中，case 标签是 constant 表达式，而不是一般的表达式.你需要一连串的 if-then-else 语句来做你想做的事情.

或者，您可以枚举开关中的值.这运行速度稍快(尽管在像你这样的情况下并不重要)，但它的可读性要差得多:

switch(score) {情况 0:cout <

When I try to compile I get this error:

1>------ Build started: Project: snake, Configuration: Debug Win32 ------
1>  exercise.cpp
1>c:users
obindocumentsvisual studio 2010projectssnakesnakeexercise.cpp(13): error C2059: syntax error : '>='
1>c:users
obindocumentsvisual studio 2010projectssnakesnakeexercise.cpp(16): error C2059: syntax error : '>='
1>c:users
obindocumentsvisual studio 2010projectssnakesnakeexercise.cpp(19): error C2059: syntax error : '>='
1>c:users
obindocumentsvisual studio 2010projectssnakesnakeexercise.cpp(22): error C2059: syntax error : '>='
1>c:users
obindocumentsvisual studio 2010projectssnakesnakeexercise.cpp(25): error C2059: syntax error : '>'
1>c:users
obindocumentsvisual studio 2010projectssnakesnakeexercise.cpp(28): error C2059: syntax error : '=='
1>c:users
obindocumentsvisual studio 2010projectssnakesnakeexercise.cpp(34): warning C4065: switch statement contains 'default' but no 'case' labels
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

Code:

#include <iostream>
using namespace std;

int main(){
    int score;

    //Vraag de score
    cout << "Score:";
    cin >> score;

    //Switch
    switch(score){
        case >= 100:
            cout << "a";
            break;
        case >= 50:
            cout << "b";
            break;
        case >= 25:
            cout << "c";
            break;
        case >= 10:
            cout << "d";
            break;
        case > 0:
            cout << "e";
            break;
        case == 0:
            cout << "f";
            break;
        default:
            cout << "BAD VALUE";
            break;
    }
    cout << endl;
    return 0;
}

How can I fix this problem? It's a console application, Win32 and my IDE is Windows Enterprise C++ 2010.

switch(score) {
    case 0: cout << "f"; break;
    case 1:
    case 2:
    case 3:
    case 4:
    case 5:
    case 6:
    case 7:
    case 8:
    case 9:
    case 10: cout << "e"; break;
    case 11:
    case 12:
    case 13:
    case 14:
    case 15:
    case 16:
    case 17:
    case 18:
    case 19:
    case 20:
    case 21:
    case 22:
    case 23:
    case 24:
    case 25: cout << "c"; break;
    // ...and so on, you get the idea...

}