// onlyme.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>
#include<stdlib.h>
using namespace std;
int inputa;
int inputb;
int Andgate(void);
int orgate(void);
int notgate(void);
int andgate(void)
{
    cout<<"input Gate A, enter 1 or 0, enter 2 to end program ";
    cin>>inputa;
    cout<<"input Gate B, enter 1 or 0, enter 2 to end program ";

    cin>>inputb;
    if (inputa == 2 || inputb == 2)
    {
        return 0;
    }


    if (inputa== 1 && inputb == 1)
    {
        cout<<"Output is logic one \n";
    }
    else
    {
        cout<<"Output is logic zerro \n";
    }

    andgate();
}
int orgate()
{
    cout << "input Gate A, enter 1 or 0, enter 2 to end program";
    cin >> inputa;
    cout << "input Gate B, enter 1 or 0, enter 2 to end program ";

    cin >> inputb;
    if (inputa == 2 || inputb == 2)
    {
        return 0;
    }
    if (inputa == 0 || inputb == 1||inputa==1||inputb==0)
    {
        cout << "Output is logic one \n";
    }
    else
    {
        cout << "Output is logic zerro \n";
    }


}
int notgate()
{
    cout << "input Gate A, enter 1 or 0, enter 2 to end program";
    cin >> inputa;
    cout << "input Gate B, enter 1 or 0, enter 2 to end program ";

    cin >> inputb;
    if (inputa == 2 || inputb == 2)
    {
        return 0;
    }
    if (inputa ==!0||inputb==!1 )
    {
        cout << "output is ligic one\n";
    }
    else
    {
        cout << "output is logic zero\n";

}
int _tmain(int argc, _TCHAR* argv[])
{
    int choice;
    while (1)
    {

        cout << " enter 1 to and gate\n enter 2 to or gate\n  enter 3 to notgate ";
        cin >> choice;
        switch (choice)
        {
        case 1:
            Andgate();
            break;
        case 2:
            orgate();
            break;
        case 3:
            notgate();
            break;
        case 4:
            exit(0);


        }

    }
    system("pause");
    return 0;
}

please correct my errors

this thread belongs to function in c++ so i am not sure why you give such a title(bitwise operator) to the thread.

however , right now , i am not familiar with functions(i can't pass any suggestions on function related issues) but i found 2 mistakes there in your code and these are :

1.you declare prototype with name Andgate(void); and defining andgate().again you done a mistake of calling Andgate();(line no.90). so the call should be andgate(); instead of Andgate();.So replace Andgate to andgate.[c++ is case sensitive language]

2.In line 77 there is missing closing curly brace. so also add curly brace at line 77.

Whats is your error and also what do you intend to achieve with your code. Give more information next time you ask for a help. We cant read your mind.