Thread: Dynamically Allocating a 2D Array.

Originally Posted by Salem

> if i did a realloc would it still trash all my previous strings?
Your realloc allocates one more char * pointer, not a string.
All your existing strings (the pointers AND the memory they point to) are preserved. You don't need to do any more work with the strings you already have.

so is

Code:

 	another quick question

Code:

for(i = 0; i < num_of_inputs; i++)
         {
            Inputs[i] = malloc(cols * sizeof(char));
         }

not needed?

Code:

#define _GNU_SOURCE 1
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <getopt.h>
#include <sys/types.h>
#include <sys/wait.h>

typedef enum
{
   FALSE = 0,
   TRUE = 1
} Bool;

int main()
{
   ssize_t readReturn = 0;
   size_t bufLen = 0;
   char **Inputs = NULL;
   void *temp;
   char *input = NULL;
   int x = 0;
   Bool stillGoing = TRUE;
   int num_of_inputs = 0;
   int cols = 0;
   int old_cols = 0;
   int i = 0;

   while(stillGoing)
   {
     printf("enter text: ");
   
     readReturn = getline(&input, &bufLen, stdin);
   
     for(x = 0; x < strlen(input) + 1; ++x)
     {
        if(input[x] == '\n')
        {
           input[x] = '\0';
        }
     }
     
     if(strncmp(input, "exit", 4) == 0)
     {
         stillGoing = FALSE;
         break;
     }
        
     num_of_inputs++;
     cols = strlen(input) +1;
     
     printf("maybe here (inputs realloc)\n");
     temp = realloc(Inputs, num_of_inputs * sizeof(char *));
     
     if(temp)
     { 
        Inputs = temp;
        Inputs[num_of_inputs - 1] = input;
     }
     else
     {
        /*handle error*/
        printf("error\n");
        exit(EXIT_FAILURE);
     }
     
     
     
     
     /*if(cols > old_cols)
      {
         for(i = 0; i < num_of_inputs; i++)
         {
            Inputs[i] = malloc(cols * sizeof(char));
         }
         old_cols = cols;
      }*/     

      printf("maybe this is where it's seg faulted (strcpy)\n");
      /* strcpy(Inputs[num_of_inputs - 1], input);*/

       
      free(input);
      input = NULL;
      free(temp);
   }
   
   
   int z = 0;
   for(z=0; i < num_of_inputs-1; z++)
   {
      printf("%s\n", Inputs[z]);
   }
   
   free(Inputs);
   return 0;
}

new code but it still prints out junk then seg faults