CODEWITHSUNDEEP
ctime
yak
yak

Reputation: 3930

Get current time in C, function

I want to get current time (without a current date) in C. The main problem is when I want to do it with functions. When I dont use them, evertyhing is just fine. Can anybody tell me, why my code shows only an hour? (take a look at the attached image). Thanks in advance.

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

char* get_time_string()
{
    struct tm *tm;
    time_t t;
    char *str_time = (char *) malloc(100*sizeof(char));
    t = time(NULL);
    tm = localtime(&t);
    strftime(str_time, sizeof(str_time), "%H:%M:%S", tm);
    return str_time;
}

int main(int argc, char **argv)
{
    char *t = get_time_string();
    printf("%s\n", t);
    return 0;
}

enter image description here

Upvotes: 1

Views: 4236

Answers (5)

Lester Lecong
Lester Lecong

Reputation: 9

In getting the time, you can try this one:

#include <stdio.h>

int main(void)
{
  printf("Time: %s\n", __TIME__);
  return 0;
}

Result:

Time: 10:49:49

Upvotes: 0

Nicolas Dusart
Nicolas Dusart

Reputation: 2007

The sizeof operator returns the length of the variable str_time which is a pointer to char. It doesn't returns the length of your dynamic array.

Replace sizeof(str_time) by 100 and it will go fine.

Upvotes: 4

Mayank Tiwari
Mayank Tiwari

Reputation: 3020

Use This Concept Getting System Time and Updating it. I have used this in my project many years before. you can change it as per your requirements.

updtime()                 /* FUNCTION FOR UPDATION OF TIME */
{
 struct time tt;
 char str[3];
 gettime(&tt);
 itoa(tt.ti_hour,str,10);
 setfillstyle(1,7);
 bar(getmaxx()-70,getmaxy()-18,getmaxx()-30,getmaxy()-10);
 setcolor(0);
 outtextxy(getmaxx()-70,getmaxy()-18,str);
 outtextxy(getmaxx()-55,getmaxy()-18,":");
 itoa(tt.ti_min,str,10);
 outtextxy(getmaxx()-45,getmaxy()-18,str);
return(0);
}
The previous function will update time whenever you will call it like 

and this will give you time

 int temp;
 struct time tt;
 gettime(&tt);                       /*Get current time*/
 temp = tt.ti_min;

If you want to update time the you can use the following code.

   gettime(&tt);
   if(tt.ti_min != temp)  /*Check for any time update */
   {
    temp = tt.ti_min;
    updtime();
   }

This is complex code but if you understand it then it will solve your all problems.

Enjoy :)

Upvotes: 0

karan
karan

Reputation: 8853

try this... 

int main ()
 {
  time_t rawtime;
  struct tm * timeinfo;

  time ( &rawtime );
  timeinfo = localtime ( &rawtime );
  printf ( "Current local time and date: %s", asctime (timeinfo) );

  return 0;
}

Upvotes: 0

simonc
simonc

Reputation: 42165

sizeof(str_time) gives you the size of char*. You want the size of the buffer str_time points to instead. Try

strftime(str_time, 100, "%H:%M:%S", tm);
//                 ^ size of buffer allocated for str_time

Other minor points - you should include <stdlib.h> to pick up a definition of malloc and should free(t) after printing its content in main.

Upvotes: 7

Related Questions