同时添加两个数字，如果用户输入字符串如何限制他

Question

在这里，我正在编写一个简单的C＃程序，将两个数字相加，但是如果用户输入字符串值，该怎么说呢？

 int x;
 int y;
 int result;
 string Res2;
 Console.Write("\n Enter the first number to be added: ");
 x = Convert.ToInt32(Console.ReadLine());
 Console.Write("\n Enter the second number to be added: ");
 y = Convert.ToInt32(Console.ReadLine());
 if (x != null && y != null)
 {
      result = x + y;
      Console.Write("\n The sum of two numbers is: " + result);

 }

Answer 1

你可以放一些像

int x;
Console.Write("\n Enter the first number to be added: ");
while(!int.TryParse(Console.ReadLine(),out x))
{
    Console.Write("\nPlease, enter a valid number: ");
}

Answer 2

如果您想在输入无效后继续执行程序，请尝试以下操作

string x,y;
int a,b;
int result;
bool flag = false;
do{
  if(flag)
  Console.Write("\n Please enter integer values");

  Console.Write("\n Enter the first number to be added: ");
  x = Console.ReadLine();
  Console.Write("\n Enter the second number to be added: ");
  y = Console.ReadLine();

  flag = true;
  }
  while(!int.TryParse(x, out a) || !int.TryParse(y, out b));

  if (x != null && y != null)
  {
     result = a + b;
     Console.Write("\n The sum of two numbers is: " + result);
  }