Errors in passing data to fuctions

[kethxenn]

So I basically have to write a simple program that accepts a username and password then requires you to confirm it again. I also have to make it so that when you confirm the password "*" appear instead of what you are typing. The problem is that when I try to compare the two inputs, it always results in failure. I tried printing out the inputted username and password and it only results in gibberish.

#include<stdio.h>
#include<conio.h>
#include<math.h>
#include<string.h>
#include<ctype.h>
#include<iostream>
using namespace std;
 char username_set()
 {
 	char username[20];
 	cout << "Please set your username:";
 	cin >> username;
 	return(username[20]);
 }
  char password_set()
 {
 	char password[20];
 	cout << "Please set your password:";
 	cin >> password;
 	return(password[20]);
 }
 int user_confirm(char input[20])
 {
 	int a;
 	char output[20],attempt[20];
 	cout << "Please input your username:";
 	cin >> attempt;
 	a=strcmp(input,attempt);
 	if(a==0)
 	{
 		cout << "Username is correct";
 	}
 	else
 	{
 		cout << "Username is wrong. Attempt = " << attempt << input;
 	}
 	return(a);
 }
 int pass_confirm(char input[20])
 {
 	int a;
 	char hold,b[20];
 	string attempt="";
 	cout << "\nPlease input your password:";
 	hold=getch();
 	while(hold!=13)
 	{
 		attempt.push_back(hold);
 		printf("*");
 		hold=getch();
 	}
	strcpy(b,attempt.c_str());
 	a=strcmp(b,input);
 	if(a==0)
 	{
 		cout << "\nPassword is correct";
 	}
 	else
 	{
 		cout << "\nPassword is wrong. Attempt = " << b << input;
 	}
 	return(a);
 	
 }
 int main(void)
 {
 	int a,b,c,attempt_user,attempt_pass;
 	char pass[20],user[20];
 	cout << "Registration process:\n";
 	user[20]=username_set();
 	pass[20]=password_set();
 	printf("\nIn order to continue, please enter your username and password\n");
 	attempt_user=user_confirm(user);
 	attempt_pass=pass_confirm(pass);
 	getch();
 }

[MiiNiPaa]

return(password[20]); It reads as "return 21st character from 20 character array"

user[20]=username_set(); reads as "get a single character from function and write it to the 21th place in 20 character array

Read more on how arrays operate.
About passing arrays to functions.
http://www.cplusplus.com/doc/tutorial/arrays/

Do not use c-strings, use std::string instead.
Do not mix C++ streams and C IO.

[kethxenn]

Thanks MiiNiPaa, managed to fix it.