C Program to determine the previous date

Program:

#include<conio.h>
#include<stdio.h>

int
main ()
{
  int month, date, year, valid = -1, leap_year = -1, invalid_input = -1;
  printf ("please enter a date = ");
  scanf ("%d", &date);
  printf ("please enter a month = ");
  scanf ("%d", &month);
  printf ("please enter a year = ");
  scanf ("%d", &year);
  if ((date > 0 && date <= 31) && (month >= 1 && month <= 12)
      && (year >= 2000 && year <= 2050))
    {
      invalid_input = 1;
      // finding given input is a leap year or not
      if ((year % 4) == 0)
  {
    leap_year = 1;
    if ((year % 100) == 0)
      {
        if ((year % 400) == 0)
    {
      leap_year = 1;
    }
        else
    {
      leap_year = -1;
    }
      }
  }
      if (month == 2 && leap_year == 1 && date > 29)
  valid = -1;
      else if (month == 2 && leap_year == -1 && date > 28)
  valid = -1;
      else
  valid = 1;
    }

  if ((month == 6 || month == 4 || month == 9 || month == 11) && date > 30)
    valid = -1;

// validating & finding output


  if (valid == 1)
    {
      printf ("Entered date = %d-%d-%d", date, month, year);

      if (date == 1)
  {
    if (month == 1)
      {
        date = 31;
        month = 12;
        year--;
      }
    else if (leap_year = 1 && month == 3)
      {
        date = 29;
        month--;
      }
    else if (leap_year == -1 && month == 3)
      {
        date = 28;
        month--;
      }
    else if (month == 2 || month == 4 || month == 6 || month == 8
       || month == 9 || month == 11)
      {
        date = 31;
        month--;
      }
    else
      {
        date = 30;
        month--;
      }
  }
      else
  {

    date--;
  }
      printf ("\nPrevious date = %d-%d-%d \n", date, month, year);
    }

  if (valid == -1 && invalid_input == 1)
    printf ("\n Not a valid date");

  if (invalid_input == -1)
    printf ("\n Invalid Input");

  return 0;
}

Output:

Testing the program:

Invalid Date:

please enter a date = 31
please enter a month = 6
please enter a year = 2030

 Not a valid date

Previous Date:

please enter a date = 21
please enter a month = 6
please enter a year = 2030
Entered date = 21-6-2030
Previous date = 20-6-2030 

Difference between wait() and sleep() in Tabular form

wait() Method

Wait method makes a thread sleep and forces it to move to suspended state.

It also causes a thread to release its acquired lock.So that, other threads can get turn in order to perform their respective jobs.
A wait method always pair with a notify method. Both together provides a way of interthread communication.

Java program to demonstrate working of wait method ?

Program:

class WaitExample extends Thread
{
 @Override
 public void run() {
 print();
 }
 synchronized void print()
 {
 System.out.println("THis is child ");
 notify();
 }
}
public class Main {
 public static void main(String[] args) {
 WaitExample thread = new WaitExample();
 thread.start();
 synchronized (thread)
 {
 System.out.println("I am in synchronised :");
 try {
 thread.wait();
 } catch (InterruptedException e) {
 e.printStackTrace();
 }
 System.out.println("I am in invoked :");
 }

Output:

sleep() Method

Sleep method puts a thread to sleep too but for specified  milliseconds.

It allows a thread to carry out its  remaining task once provided time ends. Unlike wait(), it doesn’t order a thread to release its locks until it completes its task.

Java program to demonstrate working of sleep method ?

Program:

class ThreadExample extends Thread{
    @Override
    public void run() {
        System.out.println("Child thread is about to sleep");
        try {
            sleep(3000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("I am child Thread ");
    }
}
public class Main {

    public static void main(String[] args) {
ThreadExample thread1 = new ThreadExample();
thread1.start();
        System.out.println("I am Main Thread ");
    }
}

Output

Child thread is about to sleep

 I am Main Thread
 I am child Thread

#include<stdio.h>
int main()
{
int degree;
printf("Enter degrees = ");
scanf("%d",&degree);
printf("\n %d degrees are equivalent to %.2f radians\n\n",degree,(float)(3.14*degree)/180);
return 0;
}

Output: