CS256 - Principles of Structured Design Fall 2021

Displaying ./code/cs256su21code/jun10/byRefren.c

/*

this uses call by reference

In call by reference, the location (address) of actual arguments is passed 
to formal arguments of the called function. This means by accessing the 
addresses of actual arguments we can alter them within from the called function.


In call by reference, alteration to actual arguments is possible within from 
called function; therefore the code must handle arguments carefully else you get 
unexpected results.

*/
#include <stdio.h>

//the *x means pointer to x, or where the integer x is located in memory
void doubleNum(int *x){ //we need the star in front of the variable so that we can
						// access it's location in memory
	*x = *x * 2;

}


int main(){

	int num;

	printf("Enter a number: ");
	scanf("%d", &num);

	doubleNum(&num); //similar to scanf, we need the ampersand to be able to access where
					 //num is located in memory

	printf("Double that number is %d\n", num);


}