c++ program using too much memory

Question

I have a c++ program that makes a simulation. The simulation is large. It needs to be ran several times.

I probably didn't take into account some memory management guidelines like passing arguments by reference to functions to avoid copies of the same data to be wasting memory, and maybe other techniques I don't even know about. But it is too late to redo the whole program again (or maybe it won't even help).

I have a program

void main(){

//Simulation consuming a lot of memory.

};

I would like something like

void main(){
   for (int i=0;i<10000;i++){   
     //Simulation consuming a lot of memory (depending on i).
   };
};

But in such a way that after each loop of the for the memory used inside is released (probably except that which is used for the program and the counter i of the for).

The memory holds fine for one repetition of the loop but not for two.

I there a way this can be done?

Answer 1

On UNIX/Linux, you could create a bash shell script to call your C++ program the required number of times, say run_my_app.sh with the following content:

i=0
while (( $i < 10000 )); do
    ./my_app $i
    let i+=1
done

Then make it executable with chmod +x run_my_app.sh.

---

On Windows, do the same for the cmd.exe "shell", creating run_my_app.bat with:

for /l %i in (0,1,9999) do my_app %i

You can add the full path to my_app if you need to, e.g.: c:\dir1\dir2\my_app instead of my_app. You don't need to do anything to make it executable - that's implied by the .bat extension.

---

Then modify your C++ program as follows:

#include <cstdlib>

int main(int argc, const char* argv[])
{
    if (argc != 2)
    {
         std::cerr << "usage: " << argv[0] << " i\n"
              "run the simulation iteration number <i>.\n";
         exit(EXIT_FAILURE);
    }

    int i = std::atoi(argv[1]);

    ...simulation...
}