what is the pointer error in this code?

Question

I am trying to understand pointers and here is a program in K&R that I am trying to implement. The program is strcpy with code from KR.

/*strcpy: copy t to s; pointer version 3*/
void strcpy(char *s, char *t){

while(*s++ = *t++)     
    ;              
}

So to implement this program, I add

#include<stdio.h>
int main(){

    char *s="abc", *t="ABC" ;

    strcpy(s,t);
    printf("%s\n",t);

    printf("%s\n", s);
    return 0;
}

However I am getting segmentation error when I run it. I am sure I am missing something but not quite sure what.

Thanks!

possible duplicate of [Modifying String Literal](http://stackoverflow.com/questions/5464183/modifying-string-literal) — Carl Norum, Jul 22 '13 at 05:28
possible duplicate of [Why do I get a segmentation fault when writing to a string?](http://stackoverflow.com/questions/164194/why-do-i-get-a-segmentation-fault-when-writing-to-a-string) — Krishnabhadra, Jul 22 '13 at 05:28
Possible duplicate of http://stackoverflow.com/questions/17111140/string-in-function-parameter — Jeyaram, Jul 22 '13 at 06:01

Yu Hao · Accepted Answer · 2013-07-23T00:59:32.947

8

char *s="abc", *t="ABC" ;

string literals are not modifiable, however, a char array can be modified, so change it to :

char s[] ="abc", *t="ABC" ;

edited Jul 23 '13 at 00:59

answered Jul 22 '13 at 05:29

Yu Hao

Thanks! I see the problem now! – DBS Jul 22 '13 at 05:32
+2 for offering solution, -1 for not explaining it. – This isn't my real name Jul 22 '13 at 18:17
@ElchononEdelson I thought the explanation was implied, anyway, done. – Yu Hao Jul 23 '13 at 00:59
The explanation was implied, but I feel that explication is better than implication. – This isn't my real name Jul 23 '13 at 03:14

score 7 · Answer 2 · answered Jul 22 '13 at 05:29

7

Literal string values are stored in a read-only memory page; they cannot be modified.

answered Jul 22 '13 at 05:29

Joni

2 Answers2