help with three errors(2 unqualified id, and void before token.)

[kevinskrazyklub]

/Users/Kevin/Documents/Programming/Xcode/C++/Inventoryclass/main.cpp:57: error: expected unqualified-id before 'void'
/Users/Kevin/Documents/Programming/Xcode/C++/Inventoryclass/main.cpp:67: error: expected unqualified-id before 'void'
/Users/Kevin/Documents/Programming/Xcode/C++/Inventoryclass/main.cpp:90: error: expected declaration before '}' token

i know this is kinda long but please look at these three functions:

the first error is at: Inventory::void init_inv()
the second is at: Inventory::void menu();
the last error is at the last curly brace of the menu function.

#include <iostream>
using namespace std;

const int SIZE = 100;
class Item {
	char *item;
	double cost;
	double retail;
	int on_hand;
	int lead_time;
	
	public:
		Item(char *item, double cost, double retail, int on_hand, int lead_time);
		Item(const Item &obj);
		Item();
		void setItem(char *c){item = c;}
		void setCost(double *d){cost = *d;}
		void setRetail(double *d){retail = *d;}
		void setOnHand(int *hand){on_hand = *hand;}
		void setLeadTime(int *time){lead_time = *time;}
		char *getItem(){return item;}
		double getCost(){return cost;}
		double getRetail(){return retail;}
		int getOnHand(){return on_hand;}
		int getLeadTime(){return lead_time;}
};
Item::Item(char *item, double cost, double retail, int on_hand, int lead_time){
			this->item = item;
			this->cost = cost;
			this->retail = retail;
			this->on_hand = on_hand;
			this->lead_time = lead_time;
		}
Item::Item(){
	*item = '\0';
}
/*Item::Item(char *item, double cost, double retail, int on_hand, int lead_time)
   : item( item ), cost( cost ), retail( retail ), on_hand( on_hand), lead_time( lead_time )
{
}*/

Item::Item(const Item &obj )
   : item( obj.item ), cost( obj.cost ), retail( obj.retail ), on_hand( obj.on_hand), lead_time( obj.lead_time )
{
}

class Inventory {
	Item inventory[SIZE];
	char *name;
	Inventory(char *name);
	Inventory(const Inventory &obj);
	public:
	void init_inv(), enter(), update(), display(), menu(), input();
	char *getName(){return name;}
	
};
Inventory::void init_inv(){
	
	cout << "Enter name of the inventory: ";
	cin >> name;
	
	Inventory inv1(name);
	for(int i = 0; i < SIZE; i++){
		inventory[i].item = '\n';
	}
}
Inventory::void menu(){
	char choice;
	for(;;){
			do{
				cout << "Choose one:\n\n";
				cout << "(E)nter\n(D)isplay\n(U)pdate\nQuit\n";
		
			}while(!strchr("eduq", tolower(ch));
			cin >> choice;
			switch(ch){
				case 'E': enter();
				break;
				case 'U': update();
				break;
				case 'D': display();
				break;
				case 'Q':return;
			}
		
		}
	
	}
	
}
Inventory::Inventory(char *name){
	this->name = name;
	Item inventory[SIZE] = inventory;
	}
Inventory::Inventory(const Inventory &obj)
	: name(obj.name), inventory(obj.inventory){
	}
Inventory::void input(int i){
	cout << "Item: ";
	cin >> inventory[i].item;
	
	cout << "Cost: ";
	cin >> inventory[i].price;
	
	cout << "Retail price: "
	cin >> inventory[i].retail;
	
	cout << "Quantity in stock: ";
	cin >> inventory[i].on_hand;
	
	cout << "Lead time before restock(in days): ";
	cin >> inventory[i].lead_time;
}
Inventory::void enter(){
	Item temp[SIZE+10];
	int i;
	for(i = 0; i < SIZE;i++){
		if(!*inventory[i].item)
			break;
	}
	if(i == size){
		cout << "List full!\n";
		return;
	}
	input(i);
}
Inventory::void update(){
	char *item_search;
	cout << "enter item to update:";
	cin >> *item_search;
	
	for(int i = 0; inventory[i].item;i++){
		if(!strcmp(inventory[i].item, item_search)){
			input(i);
			char ch;
			cout << "Search again? (y/n)";
			if(choice == 'y' || choice == 'Y')
				update();
				else return;
		}
		else {
			char choice;
			cout << "Item not found. Search again? (y\n): ";
			cin >> choice;
			if(choice == 'y' || choice == 'Y')
				update();
				else return;
		}
	}

}
Inventory::void display(){
	int t;
	cout << "inventory name: ";
	//sort();
	for(t = 0; t < SIZE; t++){
		if(*invntry[t].item){
			cout << inventory[t].item << '\n';
			cout << "Cost $" << invntry[t].cost << '\n';
			cout << "Retail Price $" << invntry[t].retail;
			cout << "\nOn hand: " << invntry[t].on_hand;
			cout << "\nResupply time: ";
			cout << invntry[t].lead_time << " days\n\n";
		}
	}

}

int main () {
	//cout << "Enter a name for an inventory: ";
	
	init_inv();
	
    return 0;
}