#include <library.h>

int smallest(const int w, const int x, const int y, const int z)
{ if (w < x && w < y && w < z)
    return w;
  if (x < w && x < y && x < z)
    return x;
  if (y < w && y < x && y < z)
    return y;
  return z; }

int main()
{ cout << "Type a number: ";
  const int a = read_int();
  cout << "Type a number: ";
  const int b = read_int();
  cout << "Type a number: ";
  const int c = read_int();
  cout << "Type a number: ";
  const int d = read_int();
  cout << "The smallest is " << smallest(a, b, c, d) << "\n"; }

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/*
  const int name = value;
  int name = value;       // same thing, but name's value can change at any time. Variable
  name = newvalue;        // changes that value of name. Assignment
variant
  int name;               // introduces a new variable, you don't know what its value is
*/

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#include <library.h>

int smallest(const int w, const int x, const int y, const int z)
{ int s = w;
  if (x < s)
    s = x;
  if (y < s)
    s = y;
  if (z < s)
    s = z;
  return s; }

int main()
{ cout << "Type a number: ";
  const int a = read_int();
  cout << "Type a number: ";
  const int b = read_int();
  cout << "Type a number: ";
  const int c = read_int();
  cout << "Type a number: ";
  const int d = read_int();
  cout << "The smallest is " << smallest(a, b, c, d) << "\n"; }


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bool go_again()
{ bool answer, valid = false;
  while (! valid)
  { cout << "Do you want another go? ";
    const string s = read_string();
    if (s == "yes")
    { answer = true;
      valid = true; }
    if (s == "no")
    { answer = false;
      valid = true; } }
  return answer; }

int main()
{ while (go_again())
  { print("Type a number: ");
    const int number = read_int();
    say_number(number);
    new_line(); } }

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bool go_again()
{ bool answer, valid = false;
  while (! valid)
  { cout << "Do you want another go? ";
    const string s = read_string();
    if (s == "yes")
    { answer = true;
      valid = true; }
    if (s == "no")
    { answer = false;
      valid = true; } }
  return answer; }

int main()
{ while (true)
  { print("Type a number: ");
    const int number = read_int();
    say_number(number);
    new_line();
    if (go_again() == false)
      break; } }


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#include <iostream>

using namespace std;

bool is_leap_year(const int y)
{ if (y % 400 == 0)
    return true;
  if (y % 100 == 0)
    return false;
  if (y % 4 == 0)
    return true;
  return false; }

int day_of_year(const int y, const int m, const int d)
{ int day = 0;
  if (m > 1)
    day = day + 31;
  if (m > 2)
    if (is_leap_year(y))
      day = day + 29;
    else
      day = day + 28;
  if (m > 3)
    day = day + 31;
  if (m > 4)
    day = day + 30;
  if (m > 5)
    day = day + 31;
  if (m > 6)
    day = day + 30;
  if (m > 7)
    day = day + 31;
  if (m > 8)
    day = day + 31;
  if (m > 9)
    day = day + 30;
  if (m > 10)
    day = day + 31;
  if (m > 11)
    day = day + 30;
  day = day + d;
  return day; }

int main()
{ cout << "Enter Y M D: ";
  int year, month, day;
  cin >> year >> month >> day;
  cout << year << "/" << month << "/" << day << " is day number " << day_of_year(year, month, day) << "\n"; }


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#include <iostream>

using namespace std;

double factorial(const int N)
{ int i = 1;
  double f = 1;
  while (i <= N)
  { f = f * i;
    i = i + 1; }
  return f; }

int main()
{ cout << "Type a number: ";
  int x;
  cin >> x;
  cout << x << "! = " << factorial(x) << "\n"; }

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#include <iostream>

using namespace std;

double factorial(int N)
{ double f = 1;
  while (N > 0)
  { f = f * N;
    N = N - 1; }
  return f; }

int main()
{ cout << "Type a number: ";
  int x;
  cin >> x;
  cout << x << "! = " << factorial(x) << "\n"; }