benchmarking linux and C++ program

[Man4ish]

I am benchmarking linux and C++ program to compare the results. I am testing wc -l command and C++ program doing the same but linux command wc -l is much faster than c++ progarm. Why?

#include <iostream>
#include <fstream>
using namespace std;
int main(int argc, char* argv[])
{
ifstream in(argv[1]);
char line[1000];
int count =0;
while(in)
{
in.getline(line,1000);
count++;
}
in.close();
cout << count <<endl;
return 0;
}

[gpraghuram]

HI,
The Linux commands will be much more optimized than your code and that may be one of the reason for that.
Thanks
Raghu

[Man4ish]

How can i learn such a great optimization techniques for speeding up my programs.

[Man4ish]

How can i learn such a great optimization techniques for speeding up my programs?

[Banfa]

You might not be able to but before we go there I have to ask did you compile your program with optomisation preferably speed optomisation. Normally if you compiled it for debug optomisation will be switched off. This would also explain the speed difference.

If you had optomisation on or having switch it on wc still goes faster one of the reasons is that it is likely that wc is making system calls directly. It probably benifits from being able to call the system directly being a part of the system where as your program is using standard C++ and is removed from the system by several layers.

If you still want further information then I suggest that you try looking at the source code for wc and see how they did it. This thread on the Ubuntu forums explains how to get that source code.