Obtains the CPU time used by the process #include <time.h> clock_t clock( void ); If you want to know how much CPU time your program has used, call the clock( ) function. The function's return type, clock_t, is defined in time.h as long. If the function returns -1, then the CPU time is not available. Note that the value of clock( ) does not reflect actual elapsed time, as it doesn't include any time the system may have spent on other tasks. The basic unit of CPU time, called a "tick," varies from one system to another. To convert the result of the clock( ) call into seconds, divide it by the constant CLOCKS_PER_SEC, which is also defined in time.h. Example#include <stdio.h> #include <time.h> time_t start, stop; clock_t ticks; long count; int main( ) { time(&start); for (count = 0; count <= 50000000; ++count) { if (count % 1000000 != 0) continue; /* measure only full millions */ ticks = clock( ); printf("Performed %ld million integer divisions; " "used %0.2f seconds of CPU time.\n", count / 1000000, (double)ticks/CLOCKS_PER_SEC); } time(&stop); printf("Finished in about %.0f seconds.\n", difftime(stop, start)); return 0; } This program produces 51 lines of output, ending with something like this: Performed 50 million integer divisions; used 2.51 seconds of CPU time. Finished in about 6 seconds. See Alsotime( ), difftime( ) |