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

void initialize (void);
void menu (char drink1[5][10],char drink2[5][10],char drink3[5][10],char drink4[5][10],char drink5[5][10],float price1,float price2,float price3,float price4,float price5);

int main (void)
{
	initialize ();

	return 0;
}

void initialize ()
{
	char drink1[5][10], drink2[5][10], drink3[5][10], drink4[5][10], drink5[5][10];
	float price1,price2,price3,price4,price5;

	printf("Please input the name of drink : ");
    scanf("%s",&drink1);
	printf("Enter the price of the drink : ");
	scanf("%f",&price1);

	printf("\nPlease input the name of drink : ");
	scanf("%s",&drink2);
	printf("Enter the price of the drink : ");
	scanf("%f",&price2);

	printf("\nPlease input the name of drink : ");
	scanf("%s",&drink3);
	printf("Enter the price of the drink : ");
	scanf("%f",&price3);

	printf("\nPlease input the name of drink : ");
	scanf("%s",&drink4);
	printf("Enter the price of the drink : ");
	scanf("%f",&price4);

	printf("\nPlease input the name of drink : ");
	scanf("%s",&drink5);
	printf("Enter the price of the drink : ");
	scanf("%f",&price5);

	menu (drink1,drink2,drink3,drink4,drink5,price1,price2,price3,price4,price5);

}

void menu (char drink1[5][10],char drink2[5][10],char drink3[5][10],char drink4[5][10],char drink5[5][10],float price1,float price2,float price3,float price4,float price5)
{
	int purchase;
	float coin, balance;

	printf("\n1. %s		%3.2f\n",drink1,price1);
	printf("2. %s	%3.2f\n",drink2,price2);
	printf("3. %s		%3.2f\n",drink3,price3);
	printf("4. %s		%3.2f\n",drink4,price4);
	printf("5. %s	%3.2f\n",drink5,price5);

	printf("Select a drink to purchase\n");
	scanf("%d",&purchase);
	printf("Your choice : %d\n",purchase);

	switch (purchase)
	{	
	case 1:printf("Enter coin (10, 20, 50 cents or -1 to cancel) : ");	    
		   scanf("%f",&coin);

		   if (coin==10||20||50)  /*this if doesnt work. it doesn goes to another if when i type -1 */
		   {
			   balance = ((price1*100) - coin)/100;		
			   printf("Balance : RM%3.2f\n",balance);

			   for (purchase=0;purchase<10;purchase++)		
			   {			
				   printf("Enter coin (10, 20, 50 cents or -1 to cancel) : ");	    				
				   scanf("%f",&coin);

				   if (coin==10||20||50)
				   {
						balance = ((balance*100) - coin)/100;				
						printf("Balance : RM%3.2f\n",balance);
				   }
				   if (coin==-1)
				   {
					   printf("Purchase canceled");	    
					   menu (drink1,drink2,drink3,drink4,drink5,price1,price2,price3,price4,price5);
				   }
			   }
		   }
		
		   if (coin==-1)	
		   {		
			   printf("Purchase canceled");	    
			   menu (drink1,drink2,drink3,drink4,drink5,price1,price2,price3,price4,price5);	
		   }		
		   else
		   {
				printf("Invalid\n");
		   }
	break;

	case -999:printf("Enter maintenance options\n");
		    main ();
	break;

	default:printf("Invalid\n");
		    menu (drink1,drink2,drink3,drink4,drink5,price1,price2,price3,price4,price5);
	}
}
is there something wrong with my coding? i'm looking at it and cant figure what's wrong over there.