Question

Platform: Windows XP
Processor : Dual Core

I have a program written in C Language which is compiled and its exe is formed.
My question is that will the program use both the Cores (since my machine is dual core) or I have to make my program multithreaded in order to do it ?

Answer 1

You have to implement a multithreaded program when you want to use multiple cores.

There are plenty of threading libraries out there. I’d recommend you have a look into OpenMP website, which is quite easy to integrate and use for parallization.

EDIT: a simple example:

Normally you can parallelize your for loops simply by adding:

#pragma omp parallel
for(...)

Of course, you have to link against OpenMP and compile with OpenMP support.