Assignment #3

asmt3.cpp

#include <iostream>
#include <string>

using namespace std;
const int NAccounts = 3;

string Usernames[NAccounts] = {
	"alice",
	"bob",
	"eve",
};
string Passwords[NAccounts] = {
	"secret1",
	"secret2",
	"secret3",
};

inline double sq(double x) { return x*x; }

inline int min(int a, int b) {
	if(a < b)
		return a;
	return b;
}

void
draweye(int w, int h)
{
	int x, y;
	double w1, h1;
	
	w1 = w/2.0;
	h1 = h/2.0;
	for(y = h1; y >= -h1; y--){
		for(x = -w1; x <= w1; x++){
			if(sq(x) + sq(y) >= sq(h1)
			&& sq(x)*sq(h1) + sq(y)*sq(w1) <= sq(h1)*sq(w1))
				cout << '.';
			else
				cout << ' ';
		}
		cout << endl;
	}
}

inline void
swap(int &a, int &b)
{
	int tmp;
	
	tmp = b;
	b = a;
	a = tmp;
}

void
min3(int v[], int n)
{
	int i, j, imin;

	if(n <= 3)
		return;
	for(i = 0; i < 3; i++){
		imin = i;
		for(j = i+1; j < n; j++){
			if(v[j] < v[imin])
				imin = j;
		}
		swap(v[i], v[imin]);
	}
}

bool
validuser(void)
{
	int i, j, id;
	string s;
	
	id = -1;
	i = 0;
	while(i < 3 && id < 0){
		cout << "Username: ";
		cin >> s;
		for(j = 0; j < NAccounts; j++){
			if(s == Usernames[j])
				id = j;
		}
		i++;
	}
	if(id < 0){
		return false;
	}
	for(i = 0; i < 3; i++){
		cout << "Password: ";
		cin >> s;
		if(s == Passwords[id])
			return true;
	}
	return false;
}

int
main(void)
{
	int choice, again, w, h, n, i, v[20];

	cout << "Welcome!" << endl;
	if(!validuser()){
		cout << "sorry, bye!" << endl;
		return 0;
	}
	for(;;){
		cout << "[1=eye, 2=smallest three]: ";
		cin >> choice;
		switch(choice){
		case 1:
			cout << "height: ";
			cin >> h;
			cout << "width: ";
			cin >> w;
			if((10 < h && h < 30) && (15 < w && w < 35) && w > h)
				draweye(w, h);
			break;
		case 2:
			do{
				cout << "How many numbers [<20]? ";
				cin >> n;
			}while(0 > n || n >= 20);
			cout << "Enter the numbers: ";
			for(i = 0; i < n; i++)
				cin >> v[i];
			min3(v, n);
			cout << "Smallest 3: ";
			for(i = 0; i < min(n, 3); i++)
				cout << v[i] << " ";
			cout << endl;
			break;
		default:
			cout << "invalid input" << endl;
			break;
		}
		cout << "continue? [0=no, 1=yes]: ";
		cin >> again;
		if(again == 0)
			break;
	}
	cout << "thanks bye" << endl;
	
	return 0;
}