asked on

C++ Simple Console Calculator

I am trying to create a calculator in C++ It works in a console window and allows the user to enter
the first number, a second number and then an operator such as +, -, *,
+. It will then display the result to the screen but I can not get it to compile.
The errors I am receiving are:
12 C:\Dev-Cpp\Calculator.cpp `main' must return `int'

C:\Dev-Cpp\Calculator.cpp In function `int main(...)':

15 C:\Dev-Cpp\Calculator.cpp `cout' undeclared (first use this function)

(Each undeclared identifier is reported only once for each function it appears in.)

16 C:\Dev-Cpp\Calculator.cpp `cin' undeclared (first use this function)

Here is my code:

#include <iostream.h>
#include <string.h>
#include <conio.h>
#include <dos.h>
float multiply(float firstnumber, float secondnumber)

{ return
firstnumber*secondnumber;
}
void main()

{ float firstnumber, secondnumber, answer;
char symbol;
char name[15];;
cout << "Enter number:";
cin >>firstnumber;
cout << "Enter mathematic system:";
cin >>symbol; cout << "Enter number:";
cin >> secondnumber;
switch (symbol)

{

case '+':
      answer = firstnumber+secondnumber;
      strcpy(name, "sum");
      break;
case '-':
      answer = firstnumber-secondnumber;
      strcpy(name, "difference");
      break;
case '*':
      answer = multiply(firstnumber, secondnumber);
      break;
case 'x':
      answer = multiply(firstnumber, secondnumber);
      strcpy(name, "product");
      break;
case '/':
      answer = firstnumber/secondnumber;
      strcpy(name, "quotient");
      break;

}
cout << "The " << name << " of " <<firstnumber << " and " <<secondnumber << " is "<< answer << "\n";

}

Axter

Hi mayan1,
> #include <iostream.h>

iostream.h is not part of the C++ standard, and will not compile on mondern compilers like VC++ 7.x or 8.0

I recommend you use the standard header, which does not have the .H extension
#include <iostream>
#include <string>

All STL classes are extensionless headers.

>>void main()

main needs to have a return type.
int main()
{
return 0;
}

David Maisonave (Axter)
Cheers!

Axter

#include <iostream>
#include <string>

using namespace std; //You'll need this if you don't prefix your obects with std (std::string, std::out)

itsmeandnobodyelse

Adding to above information:

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

That are the only includes and statements you need for the task (till now). Simply remove the includes of dos.h and conio.h.

>>>> char name[15];
>>>> strcpy(name, "quotient");

Use

string name;
name = "quotient";

instead.

If you want the console program keep running for further calculations you may do that:

int main()
{
float firstnumber, secondnumber, answer;
char symbol = ' ';
string name;
while (true)
{
cout << "Enter number:";
cin >>firstnumber;
cout << "Enter mathematic system:";
cin >>symbol;
if (symbol == 'q' || symbol == 'Q')
return 0;
cout << "Enter number:";
cin >> secondnumber;
switch (symbol)
{
case '+':
answer = firstnumber+secondnumber;
name = "sum";
break;
case '-':
answer = firstnumber-secondnumber;
name="difference";
break;
case '*':
answer = multiply(firstnumber, secondnumber);
break;
case 'x':
answer = multiply(firstnumber, secondnumber);
name = "product";
break;
case '/':
answer = firstnumber/secondnumber;
name = "quotient";
break;
}
cout << "The " << name << " of " <<firstnumber << " and " <<secondnumber << " is "<< answer << "\n";
}
return 0;
}

Regards, Alex

mayan1

ASKER

I am still getting errors:
17 C:\Dev-Cpp\main.cpp `cout' undeclared (first use this function)

18 C:\Dev-Cpp\main.cpp `cin' undeclared (first use this function)

29 C:\Dev-Cpp\main.cpp `name' undeclared (first use this function)

36 C:\Dev-Cpp\main.cpp `multiply' undeclared (first use this function)

C:\Dev-Cpp\Makefile.win [Build Error] [main.o] Error 1

Here is my code:

#include <iostream>
#include <string>
float multiply(float firstnumber, float secondnumber)
using namespace std;

{
returnfirstnumber*secondnumber;
}

int main()
{
float firstnumber, secondnumber, answer;
char symbol = ' ';
string name;
while (true)
{
cout << "Enter number:";
cin >>firstnumber;
cout << "Enter mathematic system:";
cin >>symbol;
if (symbol == 'q' || symbol == 'Q')
return 0;
cout << "Enter number:";
cin >> secondnumber;
switch (symbol)
{
case '+':
answer = firstnumber+secondnumber;
name = "sum";
break;
case '-':
answer = firstnumber-secondnumber;
name="difference";
break;
case '*':
answer = multiply(firstnumber, secondnumber);
break;
case 'x':
answer = multiply(firstnumber, secondnumber);
name = "product";
break;
case '/':
answer = firstnumber/secondnumber;
name = "quotient";
break;
}
cout << "The " << name << " of " <<firstnumber << " and " <<secondnumber << " is "<< answer << "\n";
}
return 0;
}

itsmeandnobodyelse

>>>> float multiply(float firstnumber, float secondnumber)

You need to add a semicolon ';' at end of that forward declaration.

Regards, Alex

mayan1

ASKER

Alex,Thank you for your help on that. I am having a terrible time understanding the compiler errors. Can you tell me what is wrong now?
Here are my errors:

6 C:\Dev-Cpp\main.cpp expected unqualified-id before '{' token
6 C:\Dev-Cpp\main.cpp expected `,' or `;' before '{' token

Here is my code:

#include <iostream>
#include <string>
float multiply(float firstnumber, float secondnumber);
using namespace std;

{
return firstnumber*secondnumber;
}

int main()
{
float firstnumber, secondnumber, answer;
char symbol = ' ';
string name;
while (true)
{
cout << "Enter number:";
cin >>firstnumber;
cout << "Enter mathematic system:";
cin >>symbol;
if (symbol == 'q' || symbol == 'Q')
return 0;
cout << "Enter number:";
cin >> secondnumber;
switch (symbol)
{
case '+':
answer = firstnumber+secondnumber;
name = "sum";
break;
case '-':
answer = firstnumber-secondnumber;
name="difference";
break;
case '*':
answer = multiply(firstnumber, secondnumber);
break;
case 'x':
answer = multiply(firstnumber, secondnumber);
name = "product";
break;
case '/':
answer = firstnumber/secondnumber;
name = "quotient";
break;
}
cout << "The " << name << " of " <<firstnumber << " and " <<secondnumber << " is "<< answer << "\n";
}
return 0;
}

ASKER CERTIFIED SOLUTION

Axter

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