简单的计算器练习

Boolean flag = true;
        while (flag) {
            char a ;
            float number1,number2,result = 0;
            printf("a表示加法\n");
            printf("b表示减法\n");
            printf("a表示乘法\n");
            printf("d表示除法\n");
            printf("q表示退出\n");
            printf("请输入您的选择:");
            scanf("%c",&a);
            switch (a) {
                case ‘a‘:
                    printf("请输入第一个数：\n");
                    scanf("%f",&number1);
                    printf("请输入第二个数：\n");
                    scanf("%f",&number2);
                    result = number1 + number2;
                    printf("%.1f + %.1f = %.1f\n",number1,number2,result);
                    break;
                case ‘b‘:
                    printf("请输入第一个数：\n");
                    scanf("%f",&number1);
                    printf("请输入第二个数：\n");
                    scanf("%f",&number2);
                    result = number1 - number2;
                    printf("%.1f - %.1f = %.1f\n",number1,number2,result);
                    break;
                case ‘c‘:
                    printf("请输入第一个数：\n");
                    scanf("%f",&number1);
                    printf("请输入第二个数：\n");
                    scanf("%f",&number2);
                    result = number1 * number2;
                    printf("%.1f + %.1f = %.1f\n",number1,number2,result);
                    break;
                case ‘d‘:
                    printf("请输入第一个数：\n");
                    scanf("%f",&number1);
                    printf("请输入第二个数：\n");
                    scanf("%f",&number2);
                    result = number1 / number2;
                    printf("%.1f + %.1f = %.1f\n",number1,number2,result);
                    break;

                case ‘q‘:
                    flag = false;
                    printf("已经退出了");
                    break;

                default:

                    break;
            }