strcat

[brent123]

I'm new to C and I'm having trouble with strcat. Can someone tell me why I get a segmentationFault error for the below code.

Thanks

char *str1 = "hello";
char *title  ;
title = strcat(str1, "World");
printf("%s",title);

 

[xwb]

You need to allocate space for it. Without any space, it is going outside what it automatically allocated

char str1[32] = "hello";  /* will allocate 32 but only use 6 */
/* Concatenate the string - works like += */
strcat (str1, "World");
printf ("%s\n", str1);

 

[cpjust]

char *str1 = "hello";

Not to mention the fact that str1 is pointing to a constant literal string, so even if you try to change it like this:

strcpy( str1, "HELLO" );

it should still blow up, since it's trying to change a constant. This may work fine on some platforms that don't enforce constant data very strictly, but it's definitely wrong and won't work on all platforms.