I'm pretty sure it's 9c/5 + 32. actually, im 100% sure.
Also, I used to make tons of those console things back in HS.
I code in C/C++/C#. also know quite a bit of ASM. If you need some GUI stuff with C/C++, I recommend looking into the FLTK wrapper. FLTK stands for Fast Light Tool Kit, it helps a bunch when making GUI's for C/C++ programs without having to go directly through the Win32 API.
also, I agree, this is not a very challenging program, I haven't looked at your code either, but it took me less than a min to whip this one up.
Code:
#include <stdio.h>
int main()
{
int celcius, fahrenheit;
printf("Enter a celcius value: ");
scanf("%i", &celcius);
fahrenheit = ((9 * celcius)/5) + 32;
printf("Fahrenheit = %i\n", fahrenheit);
system("PAUSE");
return 0;
}