Question

我试图弄清楚为什么while循环不起作用所以我添加了depIn1和value的打印语句。为什么跳过depValue1 = Double.parseDouble(depIn1)行？如果是这样，由于检查值不是真的，while循环是否仍然有效？

String depIn1 = "";
double originBalance1 = 0.00;
double newBalance1 = 0.00;
double depValue1 = 0.00;
String newNewBalance1 = "";
String originStringBalance1 = "";
boolean value;

BufferedReader depositInput1 = new BufferedReader(new InputStreamReader(System.in));
System.out.print("Amount to withdraw: ");                           
depIn1 = depositInput1.readLine();
value = isInt(depIn1);
System.out.println("depIn1: " + depIn1);
System.out.println("Value: " + value);
depValue1 = Double.parseDouble(depIn1);
System.out.println("depValue1: " + depValue1);

double doubleBalanceValue = Double.parseDouble(users.get(i).getBalance());
while((depValue1 > bankBalance) || (depValue1 <= 0) || (depValue1 > doubleBalanceValue) || (value != true)){
     System.out.print("No! Invalid input! Try again! Amount to withdraw: ");     
     depIn1 = depositInput1.readLine();
     depValue1 = Double.parseDouble(depIn1);
}
System.out.println("Thanks!");

当前输出：

Amount to withdraw: asfd
depIn1: asfd
Value: false

Answer 1

您可以尝试：

public class test {

public static void main(String[] args) throws IOException {
    String depIn1 = "";
    double originBalance1=0.00;
    double newBalance1=0.00;
    double depValue1=0.00;
    String newNewBalance1 = "";
    String originStringBalance1 = "";
    boolean value=false;

    double bankBalance = 5000.00;
    double doubleBalanceValue =5000.00;

    BufferedReader depositInput1 = new BufferedReader(new InputStreamReader(System.in));

    do{
        System.out.print("Amount to withdraw: ");                           
        depIn1 = depositInput1.readLine();
        System.out.println("depIn1: " + depIn1);
        System.out.println("Value: " + value);
        try{
        depValue1 = Double.parseDouble(depIn1);
        value=true;
        }
        catch(NumberFormatException e){
            value=false;
        }
        System.out.println("depValue1: " + depValue1);

        if(!value){
             System.out.print("No! Invalid input! Try again!");
        }
        else{
            System.out.println("Thanks!");
        }
    }
    while((depValue1 > bankBalance) || (depValue1 <= 0) || (depValue1 > doubleBalanceValue) || (value != true));

}

}

不读一行和一个while循环，我不知道为什么

1 个答案: