Call by reference help!

Hi people I need a help on call by reference this is the program I wrote but the thing is it wont call the amount of kegs and diet coke at the end please help..

Code:

#include <stdio.h>
#include <stdlib.h>

int answer,guests=0,kegs,dietCoke,pizzas;
void invitedquests();
void beverageorder(int);
int foodorder(int);
void allInfo(int,int,int,int);

int main()
{
    printf("Party Planing Assistant is pleased to be at your service!\n");
    


if you try it you will see what happens you get;
??? guests
0 kegs
0 diet coke
?? pizzas
    do
    {
     printf("a. Enter number of invited quests.\n");
     printf("b. Determine beverage order.\n");
     printf("c. Determine food order.\n");
     printf("d. Display all information.\n");
     printf("e. Quit.\n");
     
     printf("Which do you want to choose?\n");
     scanf("%c",&answer);
     printf("\n\n");
     
   
     
     if(answer=='a')
     {
     invitedquests();
     }
     else if(answer=='b')
     {
     beverageorder(guests);
     }
     else if(answer=='c')
     {
     pizzas=foodorder(guests);
     }
     else if(answer=='d')
     {
     allInfo(guests,kegs,dietCoke,pizzas);
     }
     else if(answer=='e')
     {
     }
     else
     {
     printf("please select a valid choice\n");     
     }
     
     }while(answer!='e');
     
     

system("pause");
return 0;
}

void invitedquests()
{
 int quests;
 
 printf("How many guests?\n");
 scanf("%d",&guests);
 
              
}

void beverageorder(int guests)
{
 int beerDrinker,kegs,dietCokeDrinkers,dietCoke;
 
 if(guests==0)
 {
   printf("You must enter choice a before the beverage order can be computed.\n");                
   system("pause");
   return 0;
 }
 
 else
 {
 beerDrinker=guests / 2;
 
                    if(beerDrinker %20 != 0)
                    {              
                    kegs=beerDrinker / 20 + 1;
                    }
                    else
                    {
                    kegs=beerDrinker / 20;
                    }
 
 dietCokeDrinkers=guests / 2;
 dietCoke=dietCokeDrinkers / 6;                  
 
 }    

printf("%d\n",kegs);
printf("%d\n\n\n",dietCoke);

}

int foodorder(int guests)
{
     
     
     if(guests==0)
     {
     printf("You must enter choice a before the food order can be computed.\n");                
     system("pause");
     return 0;
     }
 
     else
     {
         if(guests %4 != 0)
         {              
         pizzas=guests / 4 + 1;
         }
         else
         {
         pizzas=guests / 4;
         }
     }
return pizzas;
}

void allInfo(int guests,int kegs,int dietCoke,int pizzas)
{
     printf("%d People\n%d Kegs of Beer\n%d Cases of Diet Coke\n%d Pizzas\n",guests,kegs,dietCoke,pizzas);
}

Since this is C, not C++, there is no such thing as "pass by reference".

You are probably thinking of using pointers, which would do something like this:

Code:

void func(int *x)
{
   *x = 100;
}

int main()
{
   int a = 0;
   func(&a);
   printf("a = %d\n", a); // All being well, this will output "a = 100"
   return 0;
}

--
Mats