Example of a unique random value algorithm guaranteed by C language

Cache guarantee 1 ~ N random numbers output each time are different, and the code is short. For more information, see the code.

The code is as follows:

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// Copyright (c) cguage.com // E-mail: tangcraig@gmail.com // Date: 2014-1-21   # Include <iostream> # Include <map> # Include <cmath> # Include <iomanip> Using namespace std;   Int main (){ Map <int, int> arr; Int num = 10; Srand (time (0 ));   For (int I = 0; I <10; ++ I ){ Int idx = (num> 0? Rand () % num: 0 ); Cout <(arr. find (idx) = arr. end ()? Idx: arr [idx]) <endl; -- Num; Arr [idx] = (arr. find (num) = arr. end ()? Num: arr [num]);     }   Return 0; }

Although some examples are implemented in C language, this algorithm can be applied to C #, java, php, and other programming languages.