Function difftime () in C

The function difftime ()returns the difference between two calendar times in seconds, i.e., number of seconds elapsed between two calendar times time2 and time]. The calendar time represents the time elapsed since 00:00:00 hours 01 January 1970, GMT. The function returns the difference in seconds as a double number. The function prototype is written as follows:

double difftime (time_t Time2, time_t Time1);

Application of this function is illustrated in Program in which an initial time Timel is determined, and a second time Time2 is determined after a long calculation in the program. The difftime () computes difference of the two times.

Illustrates difftime () function

#include<stdio.h> 
 #include<time.h> 
 void main() 
 { 
   int sum = 1 ; 
   int i, j, n = 10000000; 
   time_t Time1, Time2; 
   Time1 = time(&Time1); 
   clrscr(); 
   printf("Time1 = %u\n", Time1); 
   for ( i=0 ; i<n; i++) 
     for (j=0; j<60; j++) 
       sum+= j; 
       Time2 = time(&Time2); 
       //A large loop 
       //record the time 
       printf("Time2 = %u\n", Time2); 
       printf("Difference of two times= %lf\n", difftime(Time2,Time1)); 
 }