在這個程式中，一旦例外被捕獲，程式就會顯示捕獲訊息并且程式會自行成功終止（如果想詢問用戶輸入，我需要再次手動運行程式）。我不希望程式完成，但它應該自動要求用戶輸入一個有效的數字并從頭開始執行功能，如何撰寫？
import java.util.InputMismatchException;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
try {
System.out.println("Enter a Whole Number to divide: ");
int x = sc.nextInt();
System.out.println("Enter a Whole number to divide by: ");
int y = sc.nextInt();
int z = x / y;
System.out.println("Result is: " z);
}
catch (Exception e) {
System.out.println("Input a valid number");
}
finally{
sc.close();
}
}
}
輸出
Enter a Whole Number to divide:
5
Enter a Whole number to divide by:
a
Input a valid number
Process finished with exit code 0
uj5u.com熱心網友回復：
有一些nextInt您需要注意的問題，您可以查看此鏈接：Scanner is skipping nextLine() after using next() or nextFoo()? .
對于您的程式，請使用 while 回圈，并且您需要注意 Y 可能為 0，這會導致ArithmeticException.
while (true) {
try {
System.out.println("Enter a Whole Number to divide: ");
// use nextLine instead of nextInt
int x = Integer.parseInt(sc.nextLine());
System.out.println("Enter a Whole number to divide by: ");
int y = Integer.parseInt(sc.nextLine());
if (y == 0) {
System.out.println("divisor can not be 0");
continue;
}
double z = ((double) x) / y
System.out.println("Result is: " z);
break;
}
catch (Exception e) {
System.out.println("Input a valid number");
}
}
sc.close();
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