call by reference program

I want to better understand the purpose of Call by Reference in C language

Please provide me some examples with explanation.

C doesn't have references. Nothing in C is passed by reference. Everything is a value.


Quzah.

Originally Posted by quzah

C doesn't have references. Nothing in C is passed by reference. Everything is a value.


Quzah.

Too true. If you really need to pass something "by reference", then you should have a function that expects a pointer, rather than a value. (in the case of altering pointers, then you should expect a pointer to a pointer, etc. etc.).

Code:

int someFunction(int *foo, char **bar){
    *foo=someInt;
    *bar=someString;
}
int main (char** args, int argv){
    int x=otherInt;
    char* y=otherString;
    somefunc(&x, &y);
}

The ampersand operator returns the address of the variable it is being applied to, essentially a pointer to that variable, and allows your fuction to change it. The asterisk (outside of declarations) derefrences the pointer, and returns the actual value therein, allowing you to edit it.

Thus, for any integer (say "x"):
x=the value you stored in x
&x=a pointer to that value
*x=gibberish, or a segfault, as your program tries to obtain the value of the memory address equivalent to that integer value

Hope that helps.