Sending values to another function using structures - Whats wrong with that? - c

Question

I have two functions and a structure. My first function getChange does calculations and stores them in two arrays. My second function printChange should accept these values of two arrays and just print arrays using a simple for loop.
I am trying to use my structure Change to send these arrays across to the print function, but I can't seem to do it.
I thought of creating two arrays in my structure and then simply setting array in function = to array in struct and then do the opposite in print func. But I can't!
# include <stdio.h>
#include<stdlib.h>
struct cashback{
int value[8];
int money[8];
};
typedef struct cashback Change;
int getChange(int paid, int cost){
int r, k, cntr, c=1, value[8], money[8]={200,100,50,20,10,5,2,1};
Change store;
if (cost>paid){
printf("\t Insufficient Funds! \n");
getchar();
exit(1);
}
r=paid-cost;
value[0]=r/money[0];
k=r%money[0];
for(money[c], cntr=1;cntr<8;c++, cntr++){
if (k !=0){
value[c]= k/money[c];
k=k%money[c];
}
else{
value[c]=0;
k=k/money[c];
}
}
store.value[8]=value[8];
store.money[8]=money[8]; //Sending calculation to Struct(store)
}
void printChange() {
Change store;
int i, j;
for (i=0; i<8; i++) {
printf("%i \t",store.money[i] );
}
printf("\n \n");
for (j=0; j<8; j++) {
printf("%i \t ", store.value[j] );
}
}
int main(){
Change store;
getChange(90,50);
printChange();
getchar();
}

Answer 1

When you write:
Change store;
inside a function, that means there is a variable called store inside that function only. In your code you have three separate variables (all called store).
Instead you need to pass the variable around where it is needed.
You currently have getChange returning int but you never actually return a value. Instead you should make this return the change:
Change getChange(int paid, int cost)
{
Change change;
// ...
return change;
}
Similarly, the printChange function should be:
void printChange(Change change)
{
// ...
}
and your main function will look like:
Change store;
store = getChange(90, 50);
printChange(store);

Answer 2

OK, first of all inside the 'getChange', you don't use the 'Change' struct at all. Apart from using it in this declaration: Change a;
Also, there is certainly an error here: a.value =. With what is equal?
So, the money and value arrays that you declare inside 'getChange' have nothing to do with your struct.
And finally, it doesn't seem that printChange has anything to do with the rest of the program.

Answer 3

You can pass to both functions pointer to Change structure. The structure can be defined inside main:
int getChange(int paid, int cost, Change* a){
//...
a->value[c] = ...
//...
}
void printChange(Change* a) {
//...
printf("%i \t", a->value[i]);
//...
}
int main(){
Change a;
getChange(90,50, &a);
getchar(&a);
}