整数扫描仪的n量之和

Question

我必须使用扫描仪输入未知数量的数字。一旦用户输入-1，程序需要打印输入的所有数字的总和，然后结束程序。总和中需要包含-1。

Scanner scanner = new Scanner(System.in);
int sum = 0;               

while (true) {
  int read = scanner.nextInt();
  if (read == -1) {
    break;
  }

 read = scanner.nextInt();
 sum += read;
}

System.out.println(sum);

我不能得到正确的总数。有人能帮忙吗？

Answer 1

下面的程序也将在你的总和中添加-1。您正在读取read=scanner.nextInt（）；两次。

 Scanner scanner = new Scanner(System.in);
        int sum = 0;               

        while (true) {
            int read = scanner.nextInt();


            sum += read;
            if (read == -1) {
                break;
            }
        }

        System.out.println(sum);
    }

Answer 2

Scanner scanner = new Scanner(System.in);
int sum = 0;               
int read = 0;
while (read != -1) {
   read = scanner.nextInt();
   sum += read;
}
scanner.close();
System.out.println(sum);

这在我的情况下有效。关闭扫描仪也会删除警告。

Answer 3

在您的time循环中，您使用scanner.nexInt（）将read分配两次，这会破坏您的逻辑。

Scanner scanner = new Scanner(System.in);
int sum = 0;               

while (true) {
    int read = scanner.nextInt();
    if (read == -1) {
        sum += read; //have to include -1 to sum
        break;
    }

    //read = scanner.nextInt(); you have to delete this line

    sum += read;
}

System.out.println(sum);
}