c - How to copy a string using a pointer

Question

Here's a program I wrote to copy a string constant.

When the program is run it crashes. Why is this happening ?

#include <stdio.h>

char *alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
char c;
char *l;

main(){
   while((c = *alpha++)!='')
       *l++ = *alpha;
   printf("%s
",l);
}

Answer 1

To copy strings in C, you can use strcpy. Here is an example:

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

const char * my_str = "Content";
char * my_copy;
my_copy = malloc(sizeof(char) * (strlen(my_str) + 1));
strcpy(my_copy,my_str);

If you want to avoid accidental buffer overflows, use strncpy instead of strcpy. For example:

const char * my_str = "Content";
const size_t len_my_str = strlen(my_str) + 1;
char * my_copy = malloc(len_my_str);
strncpy(my_copy, my_str, len_my_str);