#c#
Вопрос:
using System;
namespace LabExer2_CMS
{
class Program
{
double fnum;
double snum;
double answer;
string str;
static void Main(string[] args)
{
double fnum;
double snum;
double answer;
string str;
Console.WriteLine("CALCULATOR");
Console.WriteLine(" ");
Console.WriteLine("First Number: ");
fnum = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("Select an operator: ( , -, * )");
str = Console.ReadLine();
Console.WriteLine("Second Number: ");
snum = Convert.ToInt32(Console.ReadLine());
if (str == " ")
{
answer = fnum snum;
Console.WriteLine("The answer is: " answer);
}
if (str == "-")
{
answer = fnum - snum;
Console.WriteLine("The answer is: " answer);
}
if (str == "*")
{
answer = fnum * snum;
Console.WriteLine("The answer is: " answer);
}
Console.Write("PRESS ENTER TO EXIT");
Console.ReadKey();
}
}
}
Комментарии:
1. Вместо использования
Convert.ToInt32используйтеint.TryParse2. Я хочу, чтобы слово «Ошибка» появлялось, если пользователь вводит десятичное или строковое значение, отличное от «Выход».
Ответ №1:
Первый ответ лучше, но если его трудно понять, вы можете попробовать этот. Вы можете обернуть строки Console.ReadLine() try {} catch {} оператором in, затем вам нужно инициализировать fnum и snum при их объявлении. И вам также следует проверить оператора.
static void Main(string[] args)
{
double fnum = 0;
double snum = 0;
double answer;
string str;
Console.WriteLine("CALCULATOR");
Console.WriteLine(" ");
Console.WriteLine("First Number: ");
try
{
fnum = Convert.ToInt32(Console.ReadLine());
}
catch
{
Console.WriteLine("Error!");
return;
}
Console.WriteLine("Select an operator: ( , -, * )");
str = Console.ReadLine();
if (str != " " amp;amp; str != "-" amp;amp; str != "*")
{
Console.WriteLine("Wrong operator!");
return;
}
Console.WriteLine("Second Number: ");
try
{
snum = Convert.ToInt32(Console.ReadLine());
}
catch
{
Console.WriteLine("Error!");
return;
}
if (str == " ")
{
answer = fnum snum;
Console.WriteLine("The answer is: " answer);
}
if (str == "-")
{
answer = fnum - snum;
Console.WriteLine("The answer is: " answer);
}
if (str == "*")
{
answer = fnum * snum;
Console.WriteLine("The answer is: " answer);
}
Console.Write("PRESS ENTER TO EXIT");
Console.ReadKey();
}
Ответ №2:
если это вам поможет
using System;
namespace LabExer2_CMS
{
class Program
{
double fnum;
double snum;
double answer;
string str;
/// <summary>
/// Used instead of the original:
///
/// Console.WriteLine("First Number: ");
/// fnum = Convert.ToInt32(Console.ReadLine());
///
/// resp.
///
/// Console.WriteLine("Second Number: ");
/// snum = Convert.ToInt32(Console.ReadLine());
///
/// </summary>
static double getDouble(string msg) {
double res = 0;
string input = "";
bool isOk = false;
while (!isOk) {
Console.WriteLine(msg);
input = Console.ReadLine();
isOk = double.TryParse(input, out res);
if(!isOk) { Console.WriteLine("Invalid input."); }
}
return res;
}
/// <summary>
/// Used instead of the original:
///
/// Console.WriteLine("Select an operator: ( , -, * )");
/// str = Console.ReadLine();
///
/// </summary>
static string getOperator(string msg1, string[] operators) {
string res = "";
string input = "";
bool isOk = false;
string msg2 = String.Join(",", operators);
string msg = msg1 "(" msg2 ") ";
while (!isOk) {
Console.WriteLine(msg);
input = Console.ReadLine();
isOk = Array.IndexOf(operators, input) >= 0;
if(!isOk) { Console.WriteLine("Invalid input."); }
}
return res;
}
static void Main(string[] args)
{
double fnum;
double snum;
double answer;
string str;
Console.WriteLine("CALCULATOR");
Console.WriteLine(" ");
fnum = getDouble("First Number: ");
string[] operators = new string [] {" ", "-", "*"};
str = getOperator("Select an operator: ", operators);
snum = getDouble("Second Number: ");
if (str == " ")
{
answer = fnum snum;
Console.WriteLine("The answer is: " answer);
}
if (str == "-")
{
answer = fnum - snum;
Console.WriteLine("The answer is: " answer);
}
if (str == "*")
{
answer = fnum * snum;
Console.WriteLine("The answer is: " answer);
}
Console.Write("PRESS ENTER TO EXIT");
Console.ReadKey();
}
}
}