Random Numbers

• Random numbers are generated with pre-defined functions
  • Psuedo-random numbers:
    • The random numbers generated by the pre-defined functions are actually provided from a pre-computed table of random numbers, i.e., they are looked-up not produced on the spot.
    • The implication of this is that if you want a different random string between two executions, you need to begin at a random location in the table.
  • Seeding the generator:
    • The process of figuring out where to begin in the table is called "seeding the random number generator"
    • Example:  srand((unsigned int) time(0));
  • Generating a random number:
    • Example:  int randomNumber = rand();
  • Generating a number within a range:
    • The numbers generated by rand() are between 0 and MAX_INT, but what if you want a number between 1 and 100, what do you do?
    • The modulus function reduces all numbers to be between zero and the modulus.
    • For example:  int num = rand() % 100 give a number, num, between 0 and 99.
    • Add a 'base' to shift the range:  e.g., int newNum = rand() % 100 + 1;
• Random Number Generation
  • random_numbers.cpp