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



void main()
{
  int i; time_t tm1, tm2;
  char traw[20], tcomp[20];

  tm2 = time(&tm1);

  printf("time = %d = %s\n",tm2,ctime(&tm1));

  tm1 = time(0);    tm1 -= 6*24*60*60;
  strcpy(traw,ctime(&tm1));

  tcomp[0] = traw[4];  tcomp[1] = traw[8];  tcomp[2] = traw[9];
  tcomp[3] = traw[11];    tcomp[4] = traw[12];
  tcomp[5] = traw[14];    tcomp[6] = traw[15];  tcomp[7] = 0;
  i = 0;  while (tcomp[++i] != 0) if (tcomp[i] == ' ') tcomp[i] = '0';
  printf("%s ->  %s\n",traw,tcomp);

}