string is an array of char, it contains a string, while string pointer is just a pointer, which points to a string, And, string literal cannot been overwritten.

/*Desc: string and string pointer
	string is an array of char, it contains a string
	string pointer is just a pointer, which points to a string
	And, string literal cannot been overwritten.

Author: Liutong XU
*/
#include <stdio.h>
#include<string.h>
main()
{ 
	char s[81]={"Hello"};
	char *sp1,*sp2;
	printf("s = %s\n",s);
	sp1 = "Hello World!";	
                       //OK, sp1 points to a string literal "Hello World!"
	sp2 = sp1;     //OK, sp2 points to same string as sp1 does
	printf("sp1 points to: %s\n",sp1);
	printf("sp2 points to: %s\n",sp2);

	//s = "Hi";			//Not valid
	strcpy(s,"Hi");			//OK
	printf("s = %s\n",s);
	
	//strcpy(sp1,"Bye");		//Not valid; sp1 is just a pointer
	
	sp1 = s;
	printf("sp1 points to: %s\n",sp1);

	strcpy(sp1,"ByeBye");	//OK now, because sp1 points to s.
	printf("sp1 points to: %s\n",sp1);
	printf("s = %s\n",s);
	
	return 0;
}

stdout

s = Hello
sp1 points to: Hello World!
sp2 points to: Hello World!
s = Hi
sp1 points to: Hi
sp1 points to: ByeBye
s = ByeBye

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