Converting Static 2D Array to Dynamic Array in C - arrays

Question

We were asked to convert 2D static array to dynamic array. So I will need to create an array of pointers in which every pointer points to a different row. I have written this code but my code breaks when i=1 on line *(dynamicStr[i] + v) = rowStr[v]; Additionally, if I enable free(ptr); section my debugger gets stuck there for 6 or 7 times and then contiunes.
EDIT: In the end, I solved the problem with appying the answers #dodooft and #Viktor Terziev gave.
#include <stdio.h>
#include <stdlib.h>
void toDynamic(int x,int y, char toDyna[x][y]);
void toDynamic2(int x,int y, char toDyna[x][y]);
int main()
{
char toDyna[7][12] = {
"JOHN",
"MARK",
"PIERCEPIERCE",
"20",
"ROSIE",
"ALEX",
"MARLYN"
};
int x = 7;
int y = 12;
toDynamic2(x, y, toDyna);
return 0;
}
void toDynamic2(int x,int y, char toDyna[x][y]){
char *dynamicStr[x];
int rowToCheck = 0;
int size;
char *ptr;
int c;
for(int i = 0; i < x; i++){
printf("i: %d\n",i);
c = 0;
size = strlen(toDyna[rowToCheck]);
ptr = (char*) malloc(size * sizeof(char));
for(int j = 0; j < y; j++){
if(toDyna[i][j] != '\0'){
*(ptr+c) = toDyna[i][j];
c++;
} else{
break;
}
}
*(ptr+size) = '\0';
printf(" ");
char rowStr[size];
for(int v = 0; v < size; v++){
rowStr[v] = *(ptr+v);
printf("Added Char: %c\n", rowStr[v]);
*(dynamicStr[i] + v) = rowStr[v];
}
//free(ptr);
//printf("\n%s\n", rowStr);
//dynamicStr[i] = &rowStr;
rowToCheck++;
}
for(int i = 0; i < x; i++){
printf("%s\n", dynamicStr[i]);
}
}
EDIT: This is the working verion of the code:
#include <stdio.h>
#include <stdlib.h>
char** toDynamic(int x,int y, char toDyna[x][y]);
void free2DArray(int x, char **dynamicStr);
int main()
{
char toDyna[7][12] = {
"JOHN",
"MARK",
"PIERCEPIERCE",
"20",
"ROSIE",
"ALEX",
"MARLYN"
};
int x = 7;
int y = 12;
char **dynamicArr;
dynamicArr = toDynamic(x, y, toDyna);
free2DArray(x, dynamicArr);
return 0;
}
char** toDynamic(int x,int y, char toDyna[x][y]){
printf("Q2\n");
char **dynamicStr;
int rowToCheck = 0;
int size;
int c;
dynamicStr = (char*)malloc(x * sizeof(char*));
for(int i = 0; i < x; i++){
dynamicStr[i] = (char*)malloc(y * sizeof(char));
c = 0;
size = strlen(toDyna[rowToCheck]);
char *ptr = (char*) malloc((size + 1) * sizeof(char));
for(int j = 0; j < y; j++){
if(toDyna[i][j] != '\0'){
*(ptr+c) = toDyna[i][j];
c++;
} else{
break;
}
}
*(ptr+size) = '\0';
dynamicStr[i] = ptr;
rowToCheck++;
}
for(int i = 0; i < x; i++){
printf("%s\n", dynamicStr[i]);
}
printf("----------------------------\n");
return dynamicStr;
}
void free2DArray(int x, char **dynamicStr){
printf("Q3\n");
for(int i = 0; i < x; i++){
free(dynamicStr[i]);
printf("dynamicStr %d freed\n", i);
}
free(dynamicStr);
printf("dynamicStr array freed\n");
printf("----------------------------\n");
}

Answer 1

You define dynamicStr as an array of char pointers, when you are trying to assign a value to it with *(dynamicStr[i] + v) = rowStr[v]; you are basically copying the value of rowStr[v] to the address that is pointed by dynamicStr[i] + v. That address is not defined in your code, so you got a segfault.
If you are trying to fill dynamicStr with pointers to new arrays with dynamic memory, you should try something like
dynamicStr[i] = ptr;
where ptr is the pointer returned by the malloc call to the i-th row. Also, as you are working with strings you can use strcpy to copy the data from the static array to the dynamic one.

Answer 2

Its much easier than you think, please refer to strcpy documentation and strlen documentation, and (if you use my code) don't forget to free your memory.
char * * toDynamic2(size_t n, size_t m, char strings[n][m])
{
char * * arr = malloc(n * sizeof(char*));
for(size_t i = 0; i < n; ++i)
{
size_t size = strlen(strings[i]);
arr[i] = malloc((size + 1) * sizeof(char));
strcpy(arr[i], strings[i]);
}
for(size_t i = 0; i < n; ++i)
{
printf("%s\n", arr[i]);
}
return arr;
}