I'm really confused by the bug I encountered tonight. When assigning value to an element in an array, another element is changed and I can't figure out what happened. And I don't know if I used sizeof() correctly. However they seem to work fine after adding intensive output statement. The problem appears to be in line 11, but I have no idea on how to fix it. Here is my code.
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
void addstr(char ***arr, const char *str, int *size){
char *my_str=(char *)calloc(strlen(str)+1,sizeof(char));
strcpy(my_str,str);
char **new_arr=realloc(*arr,sizeof(*arr)+sizeof(char*));
/*for (int i=0;i<*size;i++)
printf("%s\n",new_arr[i]);*/
new_arr[*size]=my_str;
/*for (int i=0;i<*size;i++)
printf("%s\n",new_arr[i]);*/
*arr=new_arr;
*size=*size+1;
}
int main(){
char **mystery=0;
int size=0;
const char *ptr1="test1";
const char *ptr2="test2";
const char *ptr3="test3";
const char *ptr4="test4";
const char *ptr5="test5";
const char *ptr6="test6";
addstr(&mystery,ptr1,&size);
addstr(&mystery,ptr2,&size);
addstr(&mystery,ptr3,&size);
addstr(&mystery,ptr4,&size);
addstr(&mystery,ptr5,&size);
addstr(&mystery,ptr6,&size);
int i;
printf("\nresult:\n\nsize: %d\n",size);
for (i=0;i<size;i++)
printf("%s\n",mystery[i]);
}
The output is
result:
size: 6
test1
test3
test4
test5
test6
test2 somehow is changed. This is driving me mad cause I'm still new to c and don't know where exactly went wrong. Can anyone help please?
