System.out.format问题.%d%正

Question

它一直给我一个错误.我对%d%n部分感到困惑.任何人都可以向我解释？我想要出现金额.谢谢

System.out.println("Thank you for choosing withdrawl.");
System.out.println("How much would u like to withdrawl?");
System.out.println("1=100");
System.out.println("2=200");
System.out.println("3=300");
System.out.println("4=400");
System.out.println("5=500");
withdrawlmoney = user.nextInt();
switch(withdrawlmoney){
    case 1:  withdrawlmoneynumber = "100";
        break;
    case 2:  withdrawlmoneynumber = "200";
        break;
    case 3:  withdrawlmoneynumber = "300";
        break;
    case 4:  withdrawlmoneynumber = "400";
        break;
    case 5:  withdrawlmoneynumber = "500";
        break;
    default: withdrawlmoneynumber = "Invalid amount";
        break;
}
System.out.println(withdrawlmoneynumber);
System.out.format("the value you want to withdrawl is: %d%n" , withdrawlmoneynumber);

Answer 1

格式代码"%d"表示打印十进制数.但是你传递了一个String.数据类型withdrawalmoneynumber应为数字.

格式代码"%n"意味着打印行分隔符,这取决于平台.它可能是"\n","\r\n"或者"\r"取决于代码的运行位置.