printng the content of an array of strings

Question

I am working on some simple string related code(I am beginner in this), when I execute this code I get a warning that I don't understand. this is the code.

#include <stdio.h>
#include <unistd.h>
#include <stdint.h>

#define  Extension ".txt"
#define LOG_MIN_FILENAME_SIZE        sizeof(double) + sizeof(Extension) + 2


char* buffer[LOG_MIN_FILENAME_SIZE];
int timez = 0;
int minutes = 0;
int main()
{
    char _acBuff[LOG_MIN_FILENAME_SIZE];
    char* ListOfFiles[14];
    for(int i=0; i<14; i++){
        sprintf(_acBuff, "%d" "%d"Extension, timez, minutes);
        ListOfFiles[i]= _acBuff;
    }
    for(int i=0; i<14; i++){
        sprintf(buffer, "%s", ListOfFiles[i]);
        printf("%s", buffer);}
}

and this is the warning:

warning: Format "%s" expects Arguments of type char* but Argument 2 has type "char**" 

to my understanding I used the correct Format specifier so what exactly is the issue?

Answer 1

You want this:

#include <stdio.h>
#include <stdlib.h>   // needed for malloc
#include <string.h>   // needed for strcpy

#define  Extension ".txt"
#define LOG_MIN_FILENAME_SIZE        sizeof(double) + sizeof(Extension) + 2

char buffer[LOG_MIN_FILENAME_SIZE];   // you want an array of char, not an array of
                                      // pointers to char
int timez = 0;
int minutes = 0;
int main()
{
  char _acBuff[LOG_MIN_FILENAME_SIZE];
  char* ListOfFiles[14];
  for (int i = 0; i < 14; i++) {
    sprintf(_acBuff, "%d" "%d"Extension, timez, minutes);
    ListOfFiles[i] = malloc(strlen(_acBuff) + 1);   // allocate memory for the string
    strcpy(ListOfFiles[i], _acBuff);                // copy the string
                                                    // your code only copies the same
                                                    // pointer over and over
  }

  for (int i = 0; i < 14; i++) {
    sprintf(buffer, "%s", ListOfFiles[i]);
    printf("%s\n", buffer);   // added a \n, so output is readable
  }
}

Disclaimers:

• there is no error checking whatsoever for brevity
• allocated memory is not freed explicitely
• sizeof(double) is still wrong here, but doesn't have any consequences. You should find out yourself why.