time for execution of code

"It doesn't work" is hardly a useful problem report. Why don't you post the code that "doesn't work" and tell us what you expected it to do. Then we'll tell you what you did wrong.

Also try reading the useful information in this thread

For trivial programs, using clock() is like using a sun-dial to measure the speed of a Ferrari - "Why is it always 0, because it's too damn fast that's why!".

Even the most optimistic precision (not accuracy) figures for clock() are at least 1M times slower than the clock frequency of most modern desktop machines.

Hello Narue,

sorry i dont know ur name.i am sending you the code again.i want to find the time taken for each phase in the code: time taken for phase 1 step 1 to execute,phase1 step2..etc.when i add the clock statement in the main..it works..but it doesnt when i place it between th phases or from phase1 up to last phase.

hope u do help me.

thanks

void mix_key(   unsigned char   *key,
  unsigned char   *ta,
  unsigned long int pnl,  /* Least significant 16 bits of PN */
  unsigned long int pnh,  /* Most significant 32 bits of PN */
  unsigned char   *rc4key,
  unsigned int *p1kout
     );
/************************************************************/
/* tkip_sbox()                                              */
/* Returns a 16 bit value from a 64K entry table. The Table */
/* is synthesized from two 256 entry byte wide tables.      */
/************************************************************/
unsigned int tkip_sbox(unsigned int index)
{
   unsigned int index_low;
    unsigned int index_high;
    unsigned int left, right;
    index_low = (index % 256);
    index_high = ((index >> 8) % 256);
    left = Tkip_Sbox_Lower[index_low] + (Tkip_Sbox_Upper[index_low] * 256);
    right = Tkip_Sbox_Upper[index_high] + (Tkip_Sbox_Lower[index_high] * 256);
    return (left ^ right);
};
/****************************************************/
/* mix_key()                                        */
/* Takes a key, PN and TK. Calculates an RC4 key.   */
/****************************************************/
unsigned int rotr1(unsigned int a)
{
    unsigned int b;
    if ((a & 0x01) == 0x01)
    {
 b = (a >> 1) | 0x8000;
    }
    else
    {
 b = (a >> 1) & 0x7fff;
    }
    b = b % 65536;
    return b;
}
void mix_key(   unsigned char   *key,
  unsigned char   *ta,
  unsigned long int pnl,  /* Least significant 16 bits of PN */
  unsigned long int pnh,  /* Most significant 32 bits of PN */
  unsigned char   *rc4key,
  unsigned int *p1k
     )
{
    clock_t start = clock();
    //clock_t start1 = clock();
    /* 16 bit numbers */

    unsigned int tsc0;
    unsigned int tsc1;
    unsigned int tsc2;
    unsigned int ppk0;
    unsigned int ppk1;
    unsigned int ppk2;
    unsigned int ppk3;
    unsigned int ppk4;
    unsigned int ppk5;
    int i;
    int j;
 
    tsc0 = (unsigned int)((pnh >> 16) % 65536);  /* tsc0 is most significant */
    tsc1 = (unsigned int)(pnh % 65536);
    tsc2 = (unsigned int)(pnl % 65536);          /* tsc2 is least significant */
    /* Phase 1, step 1 */
    p1k[0] = tsc1;
    p1k[1] = tsc0;
    p1k[2] = (unsigned int)(ta[0] + (ta[1]*256));
    p1k[3] = (unsigned int)(ta[2] + (ta[3]*256));
    p1k[4] = (unsigned int)(ta[4] + (ta[5]*256));
 
    /* Phase 1, step 2 */
    for (i=0; i<8; i++)
    {
 j = 2*(i & 1);
 p1k[0] =  (p1k[0] + tkip_sbox( (p1k[4] ^ ((256*key[1+j]) + key[j])) % 65536 )) % 65536;
 p1k[1] =  (p1k[1] + tkip_sbox( (p1k[0] ^ ((256*key[5+j]) + key[4+j])) % 65536 )) % 65536;
 p1k[2] =  (p1k[2] + tkip_sbox( (p1k[1] ^ ((256*key[9+j]) + key[8+j])) % 65536 )) % 65536;
 p1k[3] =  (p1k[3] + tkip_sbox( (p1k[2] ^ ((256*key[13+j]) + key[12+j])) % 65536 )) % 65536;
 p1k[4] =  (p1k[4] + tkip_sbox( (p1k[3] ^ (((256*key[1+j]) + key[j]))) % 65536 )) % 65536;
 p1k[4] = (p1k[4] + i) % 65536;

    }

    /* Phase 2, Step 1 */
    ppk0 = p1k[0];
    ppk1 = p1k[1];
    ppk2 = p1k[2];
    ppk3 = p1k[3];
    ppk4 = p1k[4];
    ppk5 = (p1k[4] + tsc2) % 65536;
    /* Phase2, Step 2 */
    ppk0 = ppk0 + tkip_sbox( (ppk5 ^ ((256*key[1]) + key[0])) % 65536);
    ppk1 = ppk1 + tkip_sbox( (ppk0 ^ ((256*key[3]) + key[2])) % 65536);
    ppk2 = ppk2 + tkip_sbox( (ppk1 ^ ((256*key[5]) + key[4])) % 65536);
    ppk3 = ppk3 + tkip_sbox( (ppk2 ^ ((256*key[7]) + key[6])) % 65536);
    ppk4 = ppk4 + tkip_sbox( (ppk3 ^ ((256*key[9]) + key[8])) % 65536);
    ppk5 = ppk5 + tkip_sbox( (ppk4 ^ ((256*key[11]) + key[10])) % 65536);
    ppk0 = ppk0 + rotr1(ppk5 ^ ((256*key[13]) + key[12]));
    ppk1 = ppk1 + rotr1(ppk0 ^ ((256*key[15]) + key[14]));
    ppk2 = ppk2 + rotr1(ppk1);
    ppk3 = ppk3 + rotr1(ppk2);
    ppk4 = ppk4 + rotr1(ppk3);
    ppk5 = ppk5 + rotr1(ppk4);
    /* Phase 2, Step 3 */
    rc4key[0] = tsc2 % 256;
    rc4key[1] = (((tsc2 / 256) % 256) | 0x20) & 0x7f;
    rc4key[2] = (tsc2 / 256) % 256;
    rc4key[3] = ((ppk5 ^ ((256*key[1]) + key[0])) >> 1) % 256;
    rc4key[4] = ppk0 % 256;
    rc4key[5] = (ppk0 / 256) % 256;
    rc4key[6] = ppk1 % 256;
    rc4key[7] = (ppk1 / 256) % 256;
    rc4key[8] = ppk2 % 256;
    rc4key[9] = (ppk2 / 256) % 256;
    rc4key[10] = ppk3 % 256;
    rc4key[11] = (ppk3 / 256) % 256;
    rc4key[12] = ppk4 % 256;
    rc4key[13] = (ppk4 / 256) % 256;
    rc4key[14] = ppk5 % 256;
    rc4key[15] = (ppk5 / 256) % 256;
     printf("first Time Elapsed : %f\n", ((double)clock() - start) / CLOCKS_PER_SEC);
   // end= clock();

http://www.daniweb.com/forums/announcement118-3.html
Then edit your post so it's readable.

Even the most optimistic precision (not accuracy) figures for clock() are at least 1M times slower than the clock frequency of most modern desktop machines.

Not that it stops you from using clock(). All you gotta do is just put the code in a loop and run it a few 100/1000 times. You'll have your figures.