Check out example codes for "measure time in c". It will help you in understanding the concepts better.

Code Example 1

void timeWait (float threshold) {
    float timeInitial, timeMeasured, timeDelta = 0;

    timeInitial = (float)clock();
    while (timeDelta < threshold) {
        timeMeasured = (float)clock();
        timeDelta = ((timeMeasured - timeInitial) / (float)CLOCKS_PER_SEC);
    }
    printf("%.2f - %.2f s have passed.", threshold, timeDelta);
}

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