how to measure execution time c openmp

#include <stdio.h>
#include <omp.h>

int main(){

    double itime, ftime, exec_time;
    itime = omp_get_wtime();

    // Required code for which execution time has to be found
    
    ftime = omp_get_wtime();
    exec_time = ftime - itime;
    printf("\n\nTime taken is is %f", exec_gap);

}