C 语言，Switch 语句

 void main()
    {
        printf("     IT Magey      \n");
    
        int code;
    
        printf("\nEnter item code : T");
        scanf("%d", &code);
    
        double price;
        printf("Enter item price : ");
        scanf("%lf", &price);
    
        double dct;
        printf("Enter discount ('%%') : ");
        scanf("%lf", &dct );
    
        char m;
        printf("Enter payment mode (F or I): ");
        scanf("%c \n", &m);
    
        switch (m)
       {
       case 'F':
       case 'f':
        printf("\n");
    
        printf("Payment Details \n");
        printf("-----------------------------\n");
        printf("Item Code : T003256\n");
        printf("Item price: USD 2342.80\n");
    
        double dct1=price*dct/100;
        printf( "Discount: USD%lf \n", dct1);
    
        double amount1=price-dct1;
        printf("Amount to pay: USD%lf", amount1 );
        break;
    
    
       case 'I':
       case 'i':
        printf("\n");
    
        int mth;
        printf("Enter number of installments (months) : ");
        scanf("%d", &mth);
    
        printf("\n");
    
        printf("Payment Details \n");
        printf("-----------------------------\n");
        printf("Item Code : T003256\n");
        printf("Item price: USD 2342.80\n");
    
        double dct2=price*dct/100;
        printf( "Discount: USD%lf \n", dct2);
    
        double amount2=price-dct1;
        printf("Amount to pay: USD%lf", amount2 );
    
        printf("\n");
    
        printf("Number of installments : %d \n", mth);
    
        double amount3=price/mth;
        printf(" Amount to pay per installement : USD%lf", amount3 );
        break;
    
       default:
        printf("Please select only F or I");
    
    
    
    
    
       }

新手，我的 switch 语句除了默认输出之外不会显示任何输出。尽管如此，我已经添加（中断）到它仍然相同。如果除了 switch 语句之外，该程序还有其他问题，也请一并列出。谢谢:)

刚开始使用这个网站，我正在尝试填写更多细节以满足细节太少的错误：/

编辑#1：因此在将switch ('m')更改为switch(m) 后，我的输出仍然相同。如果我尝试使用 if..else if，我希望我的输出只显示“F”或“f”代码，我得到的是包含“I”和“i”代码的所有内容。