[英]Deleted files magically re-appear in VS Code Maven Java project
[英]How to make a menu re-appear in java
import java.util.*;
public class LabTest1
{
public static void main(String[] args)
{
Scanner console = new Scanner(System.in);
double Choice1;
double Choice2;
int MenuChoice;
System.out.print("Please enter the length: ");
Choice1 = console.nextDouble();
System.out.print("Please enter the width: ");
Choice2 = console.nextDouble();
System.out.println("=============================");
System.out.println("| MENU SELECTION |");
System.out.println("=============================");
System.out.println("| Options: |");
System.out.println("| 1. Calculate the area |");
System.out.println("| 2. Calculate the perimeter|");
System.out.println("| 3. Exit |");
System.out.println("=============================");
MenuChoice = console.nextInt();
System.out.print(" Select option: ");
switch (MenuChoice)
{
case 1:
System.out.println("Calculate the area selected");
System.out.println(Choice1 * Choice2);
break;
case 2:
System.out.println(" Calculate the perimeter selected");
System.out.println(2*(Choice1 + Choice2));
break;
case 3:
System.out.println("Exit selected");
System.out.println(Choice1 + Choice2);
break;
default:
System.out.println("Invalid selection");
break;
}
}
}
我需要這樣做,如果值相等,它應該顯示一條消息,說值代表一個正方形,並允許用戶重新輸入這些值,直到輸入了適當的vlaues(是的,我知道一個正方形是一個矩形)
使用以下模式來請求輸入,拒絕無效輸入並循環:
boolean isValidInput = false;
[print prompt for input]
while (!isValidInput) {
input = ...
if (input is not valid) {
print [invalid input, what is right form]
} else {
isValidInput = true;
}
}
順便說一句,您應該使用最少的文字。 打印請求和您一次執行的操作,並在每次輸入錯誤信息時提示輸入錯誤。
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