C Programming - Strings - Discussion

Program is fine except at 2 places where it dos not follow standard C language:

1) int main(void).
2) char* p1 = "India".

As per standard C language, main can have either two arguments or void:

int main(int argc, char* argv[]).
int main(void).


2nd, string literals are always constant characters, else the program behavior is undefined:

const char* = "India".

Therefore, the correct program will be:

#include<stdio.h>

int main(void)
{
char t;
const char *p1 = "India", *p2;
p2=p1;
p1 = "BIX";
printf("%s %s\n", p1, p2);
return 0;
}

Unfortunately, 3rd thing is: I wonder what was the use of introducing variable "t".

char *p1 = "India", *p2;
Here,p1 and p2 are char pointer .Difference between string and char pointer is that:1)we cannot assign a string to another whereas we can assign a char pointer to another char pointer,2)once a string has been defined,it cannot be assigned to another set of characters but such an operation is perfectly valid for char pointers.
So,in this statement, p2=p1;the value of p1 is being assigned to p2.
And,in this statement, p1 = "BIX";p1 is initialized with another value.
so, printf("%s %s\n", p1, p2);gives BIX India .

@All.

Anyone, please clear out this.

Since p1 and p2 are character pointers and p1 has been initialized with a literal string (constant) the moment a new value is assigned to p1 (p1="BIX") this value is allocated in a new area of memory. Hence p1 changes as a pointer toward a new memory location which at this point no longer coincides with p2 address (wich are the old address of p1).

Correct me if I am wrong.

Here p1, p2 are two pointers to char type.

The string content of p1 is copied to p2 by statement p2=p1 (equivalent to strcpy () statement) here no address is referenced by p2.

So if p1 changes its string value, it does not reflect in p2 value.

I think the answer given here is not corect, why because logically p2 points to p1. As p1 changes logically ps should change right?

I am confused *P means value and simply P means address. And not getting whats there in program :).

*p1="India" and p1="BIX" are the both sentences indicates same ??

Please explain the output.