Thread: C++ homework; using strings and math

Hey so this is my first ever post so I hope I am doing it right. I have been working on this homework assignment for over a week and I am so close to being done but I cannot figure out the rest. So any help would be great, and please remember I am new to C++ so this assignment might seem easy to you but it is hard for me.

Assignment: Write a C++ program that computes the value of a simple arithmeitc expression consisting of two operands (whose respective values can be either 0, 1 or 2) along with one of the standard arithmetic operators (such as +, -, * and /). Your program should input the operands along with the operator as strings.

my code so far is

Code:

#include <iostream>
#include <string>
using namespace std;

int main()
{
   string sign, firstnumber, secondnumber;  
   float value;
   int number1, number2;
                     
                // Ask user for numbers and operator
          
   cout << "Please enter the first number(zero, one or two): " << endl;
   cin >> firstnumber;
   cout << "Please enter operator(plus, minus, divide, times): " << endl;
   cin >> sign; 
   cout << "Please enter the second number(zero, one or two): " << endl;
   cin >> secondnumber;
   
      
      
          // Solve the expression  
          
     
        if(sign=="plus")
         {
         value = float(number1 + number2);
           if (value > 2)
           cout << "The expression you entered is not valid." << endl;
         else 
         cout << "The value of the expression you entered is " << value << "." << endl;
         }
       else if(sign=="minus")
         {
         value = float(number1 - number);
           if (value > 2)
           cout << "The expression you entered is not valid." << endl;
         else
         cout << "The value of the expression you entered is " << value << "." << endl;
         }
       else if(sign=="times")
         {
         value = float(number1 * number2);
           if (value > 2)
           cout << "The expression you entered is not valid." << endl;
         else
         cout << "The value of the expression you entered is " << value << "." << endl;
         }
        if(sign=="divide")
         {
         value = float(number1 / number2);
           if (value > 2)
           cout << "The expression you entered is not valid." << endl;
         else
         if (value == 0)
         cout << "Error cannot divide by zero." << endl;
         else
         cout << "The value of the expression you entered is " << value << "." << endl;
         }               
return 0;
}

I can make everything work but only if they type in 0, 1 or 2. I need to make it work when they type in zero ,one or two. But if I use the string for the number, I cannot use the string in my equation. So basically how can I convert my string into the equation the program should run like this:

Enter the first operand (zero, one or two):
zero
Enter an arithmetic operator (plus, minus, times, divide):
times
Enter the second operand (zero, one or two):
one
The value of the expression is 0.

the only way I can get all the equations to work is if I change firstnumber and secondnumber to number1 and number2 but then the inputs will not be strings, and that is part of the problem that I have to do.

no because it says "cannot assign values of type const char(2) to a variable type int

that works laserlight, but then do I have to do that for every possible equation.
0+1
0+2
0*1.....and so on?

you mean you are not allowed to just do -if first number equals zero then let number1 be 0 ?

I am confused on what you mean by "let". How would I put that in a C++ function?

laserlight that is what I have been trying to do but for some reason I cannot figure out how to do it. I want firstnumber = number1 and secondnumber = number2, so then all of my equations will work the way they are

yes laserlight, my only question really is how do I assign a string to an int? This is my first program I have ever done so I am sorry I am just confused. Is my program good so far? Is all I have to do is assign firstnumber to number1 so whatever they type in(firstnumber) will go in the equation as number1?

my problem is I do not know how to assign things