/* this is a sample program which finds maximum and calculates the
execution time */
/* compilation: cc filename.c -lm -o filename
running: filename
help: man cc -- c compiler
man times -- timing routine
man vi -- full screen editor
man dbx -- c debugger
Refer to this handout or a unix and/or a C book, if needed.
*/
/*------------------- Include Files ------------------*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <sys/times.h>
#include <sys/param.h>
#include <sys/types.h>
/*------------- Constants -----------------*/
#define maxSize 1024 /* max array size */
#define seed 10 /* seed for random number generator */
#define loop 1000 /* repeats loop times for timing accuracy */
main()
{
struct tms buffer; /* needed for timing function */
double StartTime, EndTime, ElapseTime;
int A[maxSize]; /* input array */
int max; /* variable to contain the current maximum */
int i,j; /* index variables */
srand(seed); /* initialize random number generator */
for (i=0; i<maxSize; i++)
A[i] = rand() % 1000; /* fill A with random number in the range
0 through 999; % is mod function */
StartTime = times(&buffer); /* get current time */
for (j=1; j<=loop; j++) { /* repeat max-finding 1000 times so that
the time taken would be large enough to measure */
max = A[0]; /* initialize max */
for (i=1; i < maxSize; i++) {
if (max < A[i]) max = A[i];
}
}
EndTime = times(&buffer); /* current time */
ElapseTime = EndTime - StartTime;
ElapseTime = ElapseTime / loop; /* time for a single run */
ElapseTime = ElapseTime / HZ; /* to convert into seconds */
printf("Max = %d, time taken = %f seconds \n", max, ElapseTime);
}