使用C模拟ATM练习switch..case用法

这个实例很简单，看一下就能明白，至于我已经对C比较熟悉了，为什么还要从这么简单的例子入手，这个需要再详细的说明一下。由于之前学习C的时候，就是急功近利，没有仔细的去品味C中，特别是指针中的一些乐趣，所以我选择从基础再学习一遍，就这样咯。

#include <stdio.h>

/**
 * 实现自动取款机界面的模拟来学习使用switch语句
 * switch...case语句的结构
 * switch(int类型变量){
 * case 1:   //如果是1，进行相应的处理
 *  ....
 *  break;
 * case 2:
 *  ....
 *  break;
 * default:   //可有可无的，表示如果不是上面的所有
 *  ....
 *  break;
 * }
 */
int main(void)
{
    do{
        printf("===================================\n");
        printf(":   Please select the key:        :\n");
        printf(":   1: Query                      :\n");
        printf(":   2: Credit                     :\n");
        printf(":   3: Debit                      :\n");
        printf(":   4: Return                     :\n");
        printf("===================================\n");

        int selected = 0;
        scanf("%d",&selected);

        switch(selected){
        case 1:
            printf("===================================\n");
            printf(":  Your balance is $1000          :\n");
            printf(":  Please enter any key to return :\n");
            printf("===================================\n");
            getch();
            break;
        case 2:
            printf("===================================\n");
            printf(": Please select credit money      :\n");
            printf(": 1: $50                          :\n");
            printf(": 2: $100                         :\n");
            printf(": 3: return                       :\n");
            printf("===================================\n");

            int credit = 0;
            scanf("%d",&credit);

            switch(credit){
            case 1:
                printf("===================================\n");
                printf(":  Your Credit money is $50       :\n");
                printf(":  Please enter any key to return :\n");
                printf("===================================\n");
                getch();
                break;
            case 2:
                printf("===================================\n");
                printf(":  Your Credit money is $100      :\n");
                printf(":  Please enter any key to return :\n");
                printf("===================================\n");
                getch();
                break;
            case 3:
                break;
            default:
                printf("===================================\n");
                printf(":  Op error!!                     :\n");
                printf(":  Please enter any key to return :\n");
                printf("===================================\n");
                getch();
                break;
            }
            break;
        case 3:
            printf("===================================\n");
            printf(": Please select debit money       :\n");
            printf(": 1: $50                          :\n");
            printf(": 2: $100                         :\n");
            printf(": 3: $500                         :\n");
            printf(": 4: $1000                        :\n");
            printf(": 5: return                       :\n");
            printf("===================================\n");

            int debit = 0;
            scanf("%d",&debit);

            switch(debit){
            case 1:
                printf("===================================\n");
                printf(":  Your debit money is $50        :\n");
                printf(":  Please enter any key to return :\n");
                printf("===================================\n");
                getch();
                break;
            case 2:
                printf("===================================\n");
                printf(":  Your debit money is $100       :\n");
                printf(":  Please enter any key to return :\n");
                printf("===================================\n");
                getch();
                break;
            case 3:
                printf("===================================\n");
                printf(":  Your debit money is $500       :\n");
                printf(":  Please enter any key to return :\n");
                printf("===================================\n");
                getch();
                break;
            case 4:
                printf("===================================\n");
                printf(":  Your debit money is $1000      :\n");
                printf(":  Please enter any key to return :\n");
                printf("===================================\n");
                getch();
                break;
            case 5:
                break;
            default:
                printf("===================================\n");
                printf(":  Op error!!                     :\n");
                printf(":  Please enter any key to return :\n");
                printf("===================================\n");
                getch();
                break;
            }
            break;
        case 4:
            printf("===================================\n");
            printf(":  Thank you for your using       :\n");
            printf(":  Good Bye                       :\n");
            printf("===================================\n");
            return;
        default:
            return;
        }
    }while(1);


    return 0;
}