Measuring execution time of a function in C++

Question

I want to find out how much time a certain function takes in my C++ program to execute on Linux. Afterwards, I want to make a speed comparison . I saw sever

Answer 1

simple program to find a function execution time taken.

#include 
#include  // time_t
#include 

void function()
{
     for(long int i=0;i<1000000000;i++)
     {
        // do nothing
     }
}

int main()
{

time_t begin,end; // time_t is a datatype to store time values.

time (&begin); // note time before execution
function();
time (&end); // note time after execution

double difference = difftime (end,begin);
printf ("time taken for function() %.2lf seconds.\n", difference );

return 0;
}