Thread: Changing value referred to by a character pointer

I am trying to change the value referred to by a character pointer to a character type variable after initializing it to a string literal.

Code:

#include <stdio.h>
void func7() {
    char c = 'L';
    char *p = "APPLES";
    p = &c;
    printf("%s\n", p);
}

In the output, the character 'L', which should be the only character printed, is followed by some random characters, which I think are garbage values.
I thought it was because the printf function kept printing characters until it encountered '\0' character, so I added this line

Code:

*(p + 1) = '\0';

but its giving run time error, so I used string function

Code:

strcat(p, "\0");

but even after this I am getting the same output.
Is this because %s is causing some error, or my character pointer is not pointing to a string or something else?

You are making on fundametal mistake - trying to modify a string literal (in C).

You cannot modify a string literal.

When you write 'char a = "blahblah"' it get written to the executable so what you are trying to do is to modify the executable and that will of course give you undefined behaviour.

if you want to modify the string, use:

Code:

char a[] = "string";

Originally Posted by Aslaville

You are making on fundametal mistake - trying to modify a string literal (in C).

You cannot modify a string literal.

When you write 'char a = "blahblah"' it get written to the executable so what you are trying to do is to modify the executable and that will of course give you undefined behaviour.

if you want to modify the string, use:

Code:

char a[] = "string";

but when i use

Code:

printf("%c\n", *p);

in place of

Code:

printf("%s\n", p);

then I get the expected output.
So doesn't it mean that i was getting the error because printf() was expecting a string and not because

Code:

p = &c;

is modifying the string?