Realloaction of memory in C - Arrays - c

Question

I'm starting with an array array[0] let's say.
As I loop through a text file and find keywords I'd like to store those words in that array.
So the first run though I'd assing the first keyword very simply
array[0] = "Word"
However I'm not sure how to increment that array to 1, and 2, etc.
I've read a few posts on memory allocaiton but that seemed to be specific to strings; perhaps I'm misunderstanding the concept.
I'd like to preserve the current array's contents, and increment it.
I've rigged it by setting my array[10], but I'd prefer to learn the correct way to do this.
I've included the code below so far (without any memory allocation)
#include <stdio.h>
#include <memory.h>
#include "tables.h"
int main() {
insertVarbleTble("Name","CSTRING",1,0,"");
return 0;
}
int insertVarbleTble(char *ident, char *type, int local, int constVar, char *constVal){
int successful;
int sizeArry;
sizeArry = sizeof(varible)/ sizeof(varible[0]);
if(sizeArry <= 0){
varible[sizeArry]== ident;
}else{
successful = (searchVarbleTble(ident,sizeArry)==1;
}
if(successful ==0){
varible[sizeArry+1]==ident;
}else{
printf("Already exists");
}
}
void realocMem(int size){
varible[size];
}
int searchVarbleTble(char * ident, int arrySize){
int i;
int results = 0;
for(i=0;i<arrySize;i++){
if(!strcmp(varible[i],ident)){
results= 1;
}
}
return results;
}
Header file contains the array I'm using they are:
char varible[0];
int insertVarbleTble(char *, char *, int, int , char *);
int searchVarbleTble(char *, int);
Would a potential solution be to first count the number of keywords that exist, and then dimension the array?

Answer 1

Okay generally what you want to do is not possible with arrays. Your code is really hard to understand but I will try to give you an example on how it is done.
This is not directly what you want, but should help you find your own solution. If you want to work with strings it gets a bit more complicated because strings are arrays in itself so you have to make sure that you always have enough memory for your current string available.
#include <stdio.h>
#include <stdlib.h>
typedef struct data_container_{
int *mem;
int size;
} data_container;
void add_to_memory(data_container *data, int pos, int value)
{
if (pos+1 > data->size) //check if memory for this position is allocated
{
int *dummy = realloc(data->mem, pos+1); // call realloc to get more memory
if(dummy == NULL) //check if reallocation was succesful
{
puts("Memory reallocation failed");
exit(1); //terminate program
}
else
{
data->size = pos+1; //set size to the newly allocated size
data->mem = dummy; //if succesful point to the new memory location
}
}
data->mem[pos] = value;
}
int main(void)
{
data_container data; // create stuct
data.size = 2;
data.mem = malloc(sizeof (int) * data.size); //allocate memory, similar to an array but dynamic
if(data.mem == NULL) //check if allocation was succesful
{
puts("Memory allocation failed");
exit(1); //terminate program
}
add_to_memory(&data, 0, 3); //pass the address of the struct
add_to_memory(&data, 1, 6);
add_to_memory(&data, 2, 8); //now it uses realloc, pos would be out of the allocated range
for(int i =0; i<data.size; i++)
{
printf("%d\n",data.mem[i]); //a pointer can be accessed similar to an array
}
free(data.mem); //free the allocated memory
}
as Pablo said you should read about malloc and realloc especially you should keep in mind that the memory allocated is not initialized. calloc initializes with 0.
And always remember to free allocated space when it is not used anymore.