Hi, I would like to know what lines of C code to add to a program so that it tells me the total time that the program takes to run. I guess there should be counter initialization near the beginning of main and one after the main function ends. Is the right header clock.h?

Thanks a lot...

Update I have a Win Xp machine. Is it just adding clock() at the beginning and another clock() at the end of the program? Then I can estimate the time difference. Yes, you're right it's time.h.

Here's my code:

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <share.h>
#include <time.h>


void f(long double fb[], long double fA, long double fB);

int main() {

clock_t start, end;
start = clock();


const int ARRAY_SIZE = 11;

long double* z = (long double*) malloc(sizeof (long double) * ARRAY_SIZE);

int i;
long double A, B;

if (z == NULL) {
    printf("Out of memory\n");
    exit(-1);
}

A = 0.5;
B = 2;


for (i = 0; i < ARRAY_SIZE; i++) {
    z[i] = 0;
}

z[1] = 5;

f(z, A, B);

for (i = 0; i < ARRAY_SIZE; i++)
    printf("z is %.16Le\n", z[i]);



free(z);
z = NULL;

end = clock();
printf("Took %ld ticks\n", end-start);
printf("Took %f seconds\n", (double)(end-start)/CLOCKS_PER_SEC);



return 0;  
}  

void f(long double fb[], long double fA, long double fB) {
    fb[0] = fb[1]* fA;
    fb[1] = fb[1] - 1;
    return;
 }  

Some errors with MVS2008:

testim.c(16) : error C2143: syntax error : missing ';' before 'const'  
testim.c(18) :error C2143: syntax error : missing ';' before 'type'  
testim.c(20) :error C2143: syntax error : missing ';' before 'type'   
testim.c(21) :error C2143: syntax error : missing ';' before 'type'    
testim.c(23) :error C2065: 'z' : undeclared identifier   
testim.c(23) :warning C4047: '==' : 'int' differs in levels of indirection from 'void *'  
testim.c(28) : error C2065: 'A' : undeclared identifier
testim.c(28) : warning C4244: '=' : conversion from 'double' to 'int', possible loss of data   

and it goes to 28 errors. Note that I don't have any errors/warnings without your clock codes.

LATEST NEWS: I unfortunately didn't get a good reply here. But after a search on Google, the code is working. Here it is:

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <share.h>
#include <time.h>


void f(long double fb[], long double fA, long double fB);

int main() {

clock_t start = clock();


const int ARRAY_SIZE = 11;

long double* z = (long double*) malloc(sizeof (long double) * ARRAY_SIZE);

int i;
long double A, B;

if (z == NULL) {
    printf("Out of memory\n");
    exit(-1);
}

A = 0.5;
B = 2;


for (i = 0; i < ARRAY_SIZE; i++) {
    z[i] = 0;
}

z[1] = 5;

f(z, A, B);

for (i = 0; i < ARRAY_SIZE; i++)
    printf("z is %.16Le\n", z[i]);



free(z);
z = NULL;

printf("Took %f seconds\n", ((double)clock()-start)/CLOCKS_PER_SEC);



return 0;
}

void f(long double fb[], long double fA, long double fB) {
    fb[0] = fb[1]* fA;
    fb[1] = fb[1] - 1;
    return;
}  

Cheers