CODEWITHSUNDEEP
c#
Chris Buege
Chris Buege

Reputation: 59

C#: operator '-' cannot be applied to operands of type 'string' and 'int' error

So I have almost completed my program but I keep getting this error for the subtraction operator. I have searched throughout my book and the internet but can find no fix for this. Is anybody able to tell me what is wrong with this code?

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication14
{
class Program
{
    static void Main(string[] args)
    {
        int int1;
        int int2;
        char oper;

        Console.Write("Enter first integer: ");
        int1 = Convert.ToInt32(Console.ReadLine());

        Console.Write("Enter operator (+,-,*, / or %)");
        oper = Convert.ToChar(Console.ReadLine());

        Console.Write("Enter first integer: ");
        int2 = Convert.ToInt32(Console.ReadLine());

        if(oper == '+')
            Console.Write("Answer is: " + int1 + int2);

        if (oper == '-')
            Console.Write("Answer is: " + int1 - int2);

        if(oper == '*')
            Console.Write("Answer is: " + int1 * int2);

        if(oper == '/')
            Console.Write("Answer is: " + int1 / int2);

        if(oper == '%')
            Console.Write("Answer is: " + int1 % int2);

        Console.ReadKey();
    }
}

}

Upvotes: 2

Views: 2512

Answers (4)

Plue
Plue

Reputation: 1790

Console.Write("Answer is: " + int1 - int2);

You are first concatenating a string with int1, resulting in a string. Then you try to substract this string with int2.

Try this : 

Console.Write("Answer is: " + (int1 - int2));

Thus you will first evaluate (int1 - int2) and then concatenate it.

By the way, you will also have to do it for the '+' operator. Else you will concatenate int2 to int1. For the other operators, it should work thanks to the precedence on '+'.

Upvotes: 6

Sameer
Sameer

Reputation: 2171

    if(oper == '+')
        Console.Write("Answer is: " + (int1 + int2));

    if (oper == '-')
        Console.Write("Answer is: " + (int1 - int2));

    if(oper == '*')
        Console.Write("Answer is: " + (int1 * int2);

    if(oper == '/')
        Console.Write("Answer is: " + (int1 / int2));

    if(oper == '%')
        Console.Write("Answer is: " + (int1 % int2));

Upvotes: 1

Selman Genç
Selman Genç

Reputation: 101742

Console.Write("Answer is: {0} ",int1 - int2);

Upvotes: 3

Roy Dictus
Roy Dictus

Reputation: 33149

Use a comma to separate parameters in Console.Write and use a placeholder {0}, like so:

Console.Write("Answer is: {0}", int1 - int2);

This does not confuse the compiler.

Upvotes: 1

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