Dynamic two-dimensional array of pointers to strings in C

Question

I would like to create a dynamic two-dimensional array of pointers to strings, like in the diagram below:

enter image description here

The program below is an extracted part of a program, and allocating dynamically stack A seems to work fine, but I'm having trouble creating a dynamic two-dimensional array of pointers to the cells of A.

// Global
char **stack_A; // dynamic array of strings
char ***stack_B; // dynamic array of pointers to strings
int main(){
 stack_A = malloc(sizeof(char *)); 
 stack_B = malloc(sizeof(char **));
 function(); 
 return 0;
}
void function(){
 // example for first entry 
 char *text = "some text";
 stack_A = realloc(stack_A, sizeof(char *)*strlen(text));
 stack_A[0] = strdup(text);
 
 stack_B[0] = realloc(stack_B[0], sizeof(char **));
 stack_B[0][0] = *stack_A[0];
 printf("%s", **stack_B[0][0]); // I want to output "some text"
}

Update: both the comment and answer was helpful in resolving the issue.

• Suraaj K S: stack_A = realloc(A, sizeof(char *)*strlen(text)); --> Here you increase the size of stack_A to the length of the text_string... why is that?
• Kevin: I might have gotten it wrong, but I just need to increase a cell of stack_A to make some space for "text".
• Suraaj K S: stack_B[0][0] = *stack_A[0]; The lvalue is of type char* while the rvalue is of type char...
• MikeCAT: What is A? And stack_B[0] = realloc(stack_B[0], sizeof(char **)); will invoke undefine d behavior by using value of buffer allocated via malloc() and not initialized, which is indeterminate.
• stark: char ***stack_B is not a 2D array of strings, it is a pointer to a pointer to a string.

Answer 1

The problem is that you are not copying the pointer to the string, but the first charachter of the string:

stack_B[0][0] = *stack_A[0]; -> *stack_A means the first array in the group of arrays. it means the same as stack_A[0].

*stack_A[0] means the first char in stack_A[0]: 's'

You need to copy the pointer, not the first letter: stack_B[0][0] = *stack_A[0] becomes stack_B[0][0] = stack_A[0].