programming Strings

Question

For the following program:

#include<stdio.h>
char *getString()
{
char *str = "GfG";
return str;
 }
int main()
{getString();
printf("%s", str); // Gives error, but printf("%s", getString()); works perfect.
return 0;
}

My doubt is that if we're able to return str as it is present in the shared segment of the memory and it's activation record does not get destroyed, wh can't we print the value using str? Why does the program give error saying that str is undeclared?

Answer 1

For any variable in C we have a scope beyond which we should not use it. "str" is written inside getString function and so main has no idea of it. If you make another global char pointer and assign it the value of str, you can use it inside main.

Comments

Sir but in the program, str is a pointer to a character array right...as in *str and not str[ ] which is why we are able to return the base address ( return *str; , we can't do this in case of str[ ]) , then why can't we print str?

My doubt is that since we can return str, it means that it's activation record is not destroyed right?

---

That part you are correct-- and that is why the second method works. But "what is str" is unknown to main.

Answer 2

Since 'str' is local variable to getString method,so it cannot be access by main method.
If you do like this
#include<stdio.h>
char *str;
char *getString()
{
 str = "GfG";
return str;
 }
int main()
{getString();
printf("%s", str);
return 0;
}
Output:Success    time: 0 memory: 10320 signal:0
GfG

Since 'str'  is global variable it can be access from anywhere

Answer 3

you can see this

Answer 4

because printf is a function, when you call getstring inside it, the returned result gets replaced in printf and prints it

but  when you call getstring() and dont assign anything to which the result can be stored then how will printf print it

incase you provided str=getstring();

now the reurned value gets stored, if you dont give anything where will it store the value and so it remaiins undeclared to main when printed