Just some pointer explanation I need

[blackswan]

Hi!

 
  char *c;
  c="Hello!";

Im just wondering , howcome the above stattemensts are correct. And if you printf c it would actually print "Hello" . THe pointer *c is not pointing anywhere, so it's NULL, the c is a variable so the statment is correct, but where does that variable come from?? This is confuzing me. What happens when pointer is created? Does pointer actually makes two variables, a pointer variable and a normal variable?

Regards,
Swan

[Salem]

You basically have

char anonymously_generated_by_compiler[] = "hello";
char *c;
c = anonymously_generated_by_compiler;

The string exists in memory somewhere (only the compiler knows for sure where that is), and then you set a pointer to point to it.

[blackswan]

So if I understand you correctly , first the string is made by a compiler somewhere in the memmory and then the asignment takes place.

[Salem]

Yes, the assignment being a pointer to the first location.

[blackswan]

I hoipe I can ask another question here. I want to make a function witch changes the values of two strings.

#include<stdio.h>

void switchem(char *p1, char *p2);
 int main()
  {
 
 char niz1[]="Niz1";
 char niz2[]="Niz2";
 printf(" Niz1: %s  Niz2: %s\n", niz1,niz2);
 
 switchem(&niz1,&niz2);
printf(" Niz1: %s  Niz2: %s\n", niz1,niz2);
 return 0;

 }

 void switchem(char *p1, char *p2){
  char *temp;
   temp=p2;
   p2=p1;
   p1=temp;
   
   
  }

I want the niz1="Niz2" and niz2="Niz1". I want to do this with pointers. But I get . I get an error saying: passing arg1 and arg2 to the method switchem from incompatible pointer type.

[Salem]

> I get an error saying: passing arg1 and arg2 to the method switchem from incompatible pointer type.
Well that's because you did
switchem(&niz1,&niz2);

Using & on an array results in a pointer to the array (not a pointer to a char)
switchem(niz1,niz2);
Would make the compiler happy, but then you'd need to fix the function as well.

At the moment, you only swap over copies of the pointers. You need to use strcpy() if you want to swap over what those two pointers point to.

[blackswan]

Thanks for help Salem!