Question

这是我用C＃编写的简单和新手程序。我刚尝试过整数，但是当我尝试自然输入时，它会抛出一个execption。我想知道如果发生任何字符串输入而不抛出异常，如何警告用户。（PS：我是一个荒谬的初学者）。

float quiz, mid, final,avg;
Console.WriteLine("Enter quiz score:");
quiz= float.Parse(Console.ReadLine());
Console.WriteLine("Enter mid-term score:");
mid = float.Parse(Console.ReadLine());
Console.WriteLine("Enter final score:");
final = float.Parse(Console.ReadLine());

avg=(quiz+mid+final)/3;

while (avg<=100 && quiz<=100&& mid <=100 && final<=100 )
{

    if (avg >= 90)
        Console.WriteLine("Grade A");

    else if (avg >= 70 && avg < 90)
        Console.WriteLine("Grade B");

    else if (avg >= 50 && avg < 70)
        Console.WriteLine("Grade C");

    else if (avg < 50)
        Console.WriteLine("Grade F");
    else
        Console.Write("invalid operation!!");
    break;
}
while (avg > 100)
{
    Console.WriteLine("Please enter the right scores!");
    //Console.ReadLine();
    break;
}
while (mid > 100)
{
    Console.WriteLine("Please enter the right scores!");
    //Console.ReadLine();
    break;
}
while (final > 100)
{
    Console.WriteLine("Please enter the right scores!");
    //Console.ReadLine();
    break;
}

while (quiz > 100)
{
    Console.WriteLine("Please enter the right scores!");
    //Console.ReadLine();
    break;
}
Console.ReadLine();

Answer 1

你可以试试这个：

bool isNumeric;
int i = -1;
string str = Console.ReadLine();

isNumeric = int.TryParse(str, out i);
if(isNumeric == false)
    Console.WriteLine("Not an integer");

取自here

Answer 2

我刚刚实现了＆＃34; isNumeric＆＃34;解决方案并遇到整数定义问题因为我使用浮点类型变量。我重新安排并修改了我的代码。这是最后一个正常工作版本：

bool isNumeric;
        float i;
        string str;
        string name = "";
        float quiz=0;
        float mid=0;
        float final=0;
        float avg=0;


        Console.WriteLine("Please enter your name:");
        name = Console.ReadLine();

        while (true)
        {
            Console.WriteLine("Enter quiz score:");



            str = Console.ReadLine();
            isNumeric = float.TryParse(str, out i);



            if (isNumeric)
            {

                quiz = float.Parse(str);
                if (quiz>100)
                {
                    Console.WriteLine("Please enter the right scores!");
                }
                else
                {
                    break;
                }

            }
            else
            {

                Console.WriteLine("Not an integer");


            }

        }

        while (true)
        {
            Console.WriteLine("Enter mid-term score:");
            str = Console.ReadLine();
            isNumeric = float.TryParse(str, out i);
            if (isNumeric == false)
            {
                Console.WriteLine("Not an integer");
            }
            else
            {
                mid = float.Parse(str);
                if(mid>100)
                {
                    Console.WriteLine("please input the right score");
                }
                else
                {
                    break;
                    }


            }
        }

        while (true)
        {
            Console.WriteLine("Enter final score:");
            str = Console.ReadLine();
            isNumeric = float.TryParse(str, out i);
            if (isNumeric == false)
            {
                Console.WriteLine("Not an integer");
            }
            else
            {
                final = float.Parse(str);
                if (final > 100)
                {
                    Console.WriteLine("Please enter the right scores!");
                }
                else
                {
                    break;
                }
            }
        }

        avg = (quiz + mid + final) / 3;

        while (avg <= 100 && quiz <= 100 && mid <= 100 && final <= 100)
        {

            if (avg >= 90)
                Console.WriteLine(name+" 's Grade is A");

            else if (avg >= 70 && avg < 90)
                Console.WriteLine(name+ " 's Grade is B");

            else if (avg >= 50 && avg < 70)
                Console.WriteLine(name+ "Grade C");

            else if (avg < 50)
                Console.WriteLine("Grade F");
            else
                Console.Write("invalid operation!!");
            break;
        }


        Console.ReadLine();

如果他/她输入＆＃34;字符串＆＃34;如何警告用户而不是＆＃34;整数＆＃34;在C＃控制台？

2 个答案: