How to use Dynamic Allocation for char array

You have to allocate memory and then reallocate. Here an example:

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

int main(void) {

    //allocate a buffer of 10 pointers
    size_t array_size = 10;
    char ** array=(char **)malloc(array_size * sizeof(*array) );
    if (!array)
        return -1;

    //now allocate the 10 pointers with a buffer to hold 42 characters
    for (int i = 0; i < array_size; i++) {
        array[i]= (char *)malloc( 42 * sizeof (*array[i]) );
        if (!array[i])
            return -1;
        strcpy(array[i], "10");
    }

    //for some reason we need to increase array size by 1
    ++array_size;
    array = (char **)realloc(array, array_size * sizeof(*array) );
    array[array_size-1] = (char *)malloc(42 * sizeof(*array[array_size-1]) );
    if (!array[array_size-1])
        return -1;
    strcpy(array[array_size-1], "12");
}