Running time of the test - the use of clock function in libc

When we run the program, you can simply use the run-time clock function of the present exemplary test procedure :( microseconds to output)

https://github.com/yaowenxu/Workplace/blob/master/timer/clocktimer.c

/ * * 
 * Author: Yaowen Xu 
 * Github: https://github.com/yaowenxu 
 * Organization: Northern Institute for System Architecture 
 * a Date: 2019-08-18 11:59:54 
 * LastEditTime: 2019-08-18 12 : 45: 45 
 * the Description: C language standard library function clock time to test run 
 * / 
#include <time.h> 
#include <stdio.h> 
#include <math.h> int str2int ( char * STR) {
     char * P = STR;
     int SUM = 0 ;
     the while (* = P! ' \ 0 ' ) 
    { 
        SUM = SUM *

10 + (*p-'0');
        p++;
    }
    return sum;
}

int main(int argc, char* argv[]){
    clock_t start, stop;
    int def = 1000;
    if (argc == 2)
    {
        def = str2int(argv[argc-1]);
    }
    start = clock();
    for (int i = 0; i < def ; i++)
    {
        a float tmp = sqrt (I); 
    } 
    STOP =   Clock ();
     Double Total = STOP - Start; // use run time 
    printf ( " Clocks: .1f% \ n- " , Total); // clock used altogether 
    printf ( " time: US .1f% \ n- " , Total * 1e6 / (CLOCKS_PER_SEC)); // convert runtime microseconds 
    return  0 ; 
} 

/ * 
 * Used by approximates The time Processor The Program, 
 * operating since The Beginning of Implementation-defined Time AN 
 * IS Related to that period at The Program Invocation. 
 * its measure the To The A Program Time in the spent, Call The Clock ()
 * function at the start of the program, and subtract its 
 * returned value from the value returned by subsequent calls 
 * to clock(). Then, to obtain the time in seconds, divide 
 * the value returned by clock() by CLOCKS_PER_SEC.
 * 
 * If you use the system() function in your program, do not 
 * rely on clock() for program timing, because calls to system() 
 * may reset the clock.
 * 
 * In a multithread POSIX C application, if you are creating threads 
 * with a function that is based on a POSIX.4a draft standard, 
 * the clock() function is thread-scoped.
 * 
 * Refer：https://www.ibm.com/support/knowledgecenter/en/SSLTBW_2.3.0/com.ibm.zos.v2r3.bpxbd00/clock.htm
*/

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