C # verify the birthday paradox using a simulated program,

C # verify the birthday paradox using a simulated program,

The birthday paradox indicates that if there are 23 or more people in a room, the probability of two people having the same birthday is greater than 50%, which is about 50.7, this means that in a typical standard primary school class (30 persons), there is a higher possibility of two persons having the same birthday. For 60 or more people, this probability is greater than 99%. From the perspective of logical conflicts, the birthday paradox is not a paradox. in the sense that this mathematical fact conflicts with General intuition, it can be called a paradox. Most people think that the probability of two people with the same birthday in 23 should be much less than 50%.

This result can be calculated using mathematical formulas. Instead of using the formula, we can directly use a program to simulate the generation of a room, which contains 23 persons and check whether there are birthday duplicates. Repeat multiple times to accumulate the results. The following is the source code (console program)

Using System; using System. threading; namespace ConsoleApplication1 {class Program {// a date, a random device, used to generate a random birthday private static DateTime dt = Convert. toDateTime ("12-31"); private static Random ran = new Random (); /// <summary> /// number of rooms /// </summary> private static int roomNumber = 0; /// <summary> /// number of qualified rooms /// </summary> private static int roomRight = 0; /// <summary> /// number of attempts /// </summary> private Static int test = 0; static void Main (string [] args) {Console. writeLine ("Enter the number of executions, which can only be an integer"); try {test = Convert. toInt32 (Console. readLine (); Thread t1 = new Thread (new ThreadStart (start); t1.Start ();} catch {Console. writeLine ("incorrect input. Please run it again. ");} Console. readLine () ;}//< summary> /// start the simulated test /// </summary> private static void start () {for (int I = 0; I <test; I ++) {DateTime [] dtRoom = creatRoom (); if (checkBirsday (dtRoom) = true) roomRight ++; Console. writeLine ("remaining:" + (test-I ). toString ();} float probability = Convert. toSingle (roomRight)/Convert. toSingle (roomNumber); Console. writeLine (String. format ("A total of {0} rooms, matching {1} rooms, probability {2} ", roomNumber, roomRight, probability) ;}/// <summary> // generate a room, contains 23 random birthdays /// </summary> /// <returns> </returns> private static DateTime [] creatRoom () {DateTime [] people = new DateTime [23]; for (int I = 0; I <people. length; I ++) {people [I] = creatBirsday ();} roomNumber ++; return people ;} /// <summary> /// randomly generate a date /// </summary> /// <returns> </returns> private static DateTime creatB Irsday () {int RandKey = ran. next (0,365); DateTime dtBirsday = dt. addDays (RandKey * (-1); return dtBirsday ;} /// <summary> /// check whether there are duplicate birthdate items in the room /// </summary> /// <param name = "dtBrisday"> </param> // /<returns> </returns> private static bool checkBirsday (DateTime [] dtBrisday) {for (int I = 0; I <dtBrisday. length; I ++) {int id = Array. indexOf (dtBrisday, dtBrisday [I]); // here 1 is the value you want to find if (id! =-1 & id! = I) return true;} return false ;}}}View Code

Running result