How do I generate a random number between two variables that I have stored

Question

Possible Duplicate    Generating random integer from a range       I am trying to create a program where the computer guesses a number the user has in his her mind  The only user input required is whether the guess was too high  too low  or correct  I m having a problem generating a random number between two variables that store the min and max based on previous guesses  Here is my code        include  lt iostream gt       include  lt cstdlib gt       include  lt ctime gt       using namespace std       int main                 srand static cast  lt unsigned int gt   time 0              int compGuess   rand     100  1    Generates number between 1 - 100         int highestNumber   100          int lowestNumber   1          char ready          char highLowSuccess          bool success          int tries   0            cout  lt  lt   Please pick a number between 1 - 100  I will guess your number  Don t tell me what it is  n n             do                       cout  lt  lt   Are you ready   y n  n n               cin  gt  gt  ready               if  ready     y                                 do                                       cout  lt  lt   Is your number    lt  lt  compGuess  lt  lt     n n                       cout  lt  lt   High  Low or Success                          tries                      cin  gt  gt  highLowSuccess    User input telling the computer whether its too high  too low  or a success                      if  highLowSuccess     h     Executes code if number guessed was too high                                                 highestNumber   compGuess - 1    Stores variable indicating the highest possible number based on user input                         compGuess   rand     highestNumber  1    Generates a new random number between 1 and the new highest possible number                         success   false                                             else if  highLowSuccess     l     Executes code if number guessed was too low                                                lowestNumber   compGuess   1   Stores variable indicating the lowest possible number based on user input                         compGuess    rand     highestNumber - lowestNumber   1    lowestNumber     lt ---- Not producing the desired result                         success   false                                             else if  highLowSuccess     s     Executes code if the computer s guess was correct                                                cout  lt  lt   I guessed your number  It only took me    lt  lt  tries  lt  lt    tries                            success   true                                            while  success    true                               else                            continue                          while  ready     y           return 0           highestNumber is what the max should be and lowestNumber is what the min should be  I need an equation that lets me generate a random number while taking the highest and lowest possible numbers into account   Forgive me if the answer is really simple  I m a noob programmer  xD

User · Answer

If you have a C  11 compiler you can prepare yourself for the future by using c   s pseudo random number faculties     make sure to include the random number generators and such  include  lt random gt    the random device that will seed the generator std  random device seeder    then make a mersenne twister engine std  mt19937 engine seeder       then the easy part    the distribution std  uniform int distribution lt int gt  dist min  max     then just generate the integer like this  int compGuess   dist engine     That might be slightly easier to grasp  being you don t have to do anything involving modulos and crap    although it requires more code  it s always nice to know some new C   stuff     Hope this helps - Luke

User · Answer

To generate a random number between min and max  use   int randNum   rand    max-min   1    min     Includes max and min

User · Answer

rand       highestNumber - lowestNumber    1    lowestNumber

User · Answer

Really fast  really easy   srand time NULL       Seed the time int finalNum   rand    max-min 1  min     Generate the number  assign to variable    And that is it  However  this is biased towards the lower end  but if you are using C   TR1 C  11 you can do it using the random header to avoid that bias like so    include  lt random gt   std  mt19937 rng seed   std  uniform int distribution lt int gt  gen min  max      uniform  unbiased  int r   gen rng     But you can also remove the bias in normal C   like this   int rangeRandomAlg2  int min  int max       int n   max - min   1      int remainder   RAND MAX   n      int x      do          x   rand         while  x  gt   RAND MAX - remainder       return min   x   n      and that was gotten from this post

[c++] How do I generate a random number between two variables that I have stored?

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