我在“开始”时遇到错误。在底部的（开始+结束）

Question

我在＆＃39; start＆＃39;上收到错误在底部的（开始+结束）。修复它的唯一方法是添加＆＃34; int start = inputFn.nextInt（）;＆＃34;下面＆＃39;扫描仪输入Fn =新扫描仪（System.in）;＆＃39;但这一切搞砸了。之前我能够解决它，但我忘了我是怎么做到的。请帮忙。

public static void main(String eth[]){

System.out.println("Please Enter An Integer:");
Scanner inputFn = new Scanner(System.in);


if (inputFn.hasNextInt()){
}else{
int start = inputFn.nextInt();
System.out.print("Play By The Rules And Enter An Integer");

}

System.out.println("Please Enter An Integer:");
Scanner inputSn = new Scanner(System.in);
int finish = inputSn.nextInt();

int answer = (start + finish);
System.out.println(answer);


}
}

Answer 1

if

if (inputFn.hasNextInt()){
}else{
  int start = inputFn.nextInt();
  System.out.print("Play By The Rules And Enter An Integer");
}

有点倒退。只有在没有整数时才读取整数。而且你在if块中定义了start变量，这就是你得到错误的原因。

更像是

int start = 0;
if (inputFn.hasNextInt()){
  start = inputFn.nextInt();
}else{
  System.out.print("Play By The Rules And Enter An Integer");
}

似乎更好。