Thread: C++ homework; using strings and math

Code:

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

int main()
{
   string operation, 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 >> operation; 
   cout << "Please enter the second number(zero, one or two): " << endl;
   cin >> secondnumber;
   
      
          // Solve the expression  
     if(firstnumber == "zero")
      {
          number1 = 0;
      }
     else if(firstnumber == "one")
      {
         number1 = 1;
      }
     else if(firstnumber == "two")
      {
        number1 = 2;
      }
     if(secondnumber == "zero")
     {
       number2 = 0;
     }  
    else if(secondnumber == "one")
     {
       number2 = 1;
     } 
    else if(secondnumber == "two")
     {
       number2 = 2;
     }  

     if(operation=="plus")
         {
         value = (number1 + number2);
         cout << "The value of the expression you entered is " << value << "." << endl;
         }
       else if(operation=="minus")
         {
         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(operation=="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(operation=="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;
}

Wow thanks guys, everything works now once I figure out how to make 1/2=.5...thank you guys so much I have been working on this for over a week and it is due at 930 tonight so thanks again

well it looks like I ran into another problem I didnt even know about. If the person typing in the numbers types in Two instead of two, it is suppose to say error..Is there a way to make it so if the word is capitalized it will say error or do I have to assign each one individually?

it says no such namespace std::tolower

this is what the program is suppose to do

Good
Enter the first operand (zero, one or two):
one
Enter an arithmetic operator (plus, minus, times, divide):
plus
Enter the second operand (zero, one or two):
two
The value of the expression you entered is 3.

Bad
Enter the first operand (zero, one or two):
Two
Enter an arithmetic operator (plus, minus, times, divide):
plus
Enter the second operand (zero, one or two):
two
The expression that you entered is not valid.

I can do the good part fine, I just cannot do the bad part

I also cannot use tolower. We cannot use functions loops or arrays

You can actually use tolower, it's just that it actually looks like this:

Code:

std::transform (aString.begin(), aString.end(), aString.begin(), ::tolower);

I forget the exact reason why, but it seems to be a problem whenever you want to use anything from C like this (e.g. tolower(), rand()). It's not clear to me why std::anythingFromC does not resolve to a function pointer.

Also, since this was left unresolved by Elysia, if the first three arguments to transform are the same container, it only means that the transformation occurs in place.