BASIC11

BASIC11.WPS

BASIC LANGUAGE PROGRAMMING

USING RANDOM NUMBERS

Random numbers may be generated for use in BASIC programs

by using the RND function. When the RND function is called,

it returns a number between 0 and .999999

We can make a random number generator in BASIC to generate

random numbers between 0 and 10, by using the following

statement: LET X = INT (RND*10) The INT function forces the computer to

output an integer. Similarly, a random number generator can be made for

numbers between 0 and 100 by using the statement: LET X = INT (RND*100)

NOTE: Random numbers are generated when the computer takes a "seed" number

from within itself. It runs this number through an algorithm which returns a value between

0 and .999999. The computer will always take the same seed and therefore

return the same series of numbers unless otherwise instructed. This is useful for

troubleshooting programs because you know what values the machine will generate!

To generate a different series of numbers we simply change the seed number.

You can specify a seed by including say a RANDOMIZE 100 or RANDOMIZE 10

instruction. The number following the word RANDOMIZE is the "seed" number.

To have truly random numbers the seed number must change each time the program

is run. To accomplish this place a RANDOMIZE TIMER statement in your program.

The timer function takes the number of elapsed seconds since midnight from the

computer's internal clock and will ALWAYS be different!

THE WORD "RANDOMIZE" MUST BE INCLUDED IN THE PROGRAM

Here is an example of a simple program which generates random numbers between

1 and 30

REM THIS PROGRAM GENERATES AND PRINTS A RANDOM NUMBER

BETWEEN REM 1 AND 30

RANDOMIZE

LET X = INT (RND*30)

PRINT X

END

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Assignment - Write programs to do the following:

1) Use a random number generator to generate an integer

between 1 and 20 and then have the user guess the

value of the number. The computer is to give the user

hints by telling him/her if his/her last guess was high

or low. The program should congratulate the user when

he or she finally guesses the correct number.

2) Write a program to help your younger brother with his

math. The program should use random number generators

to generate 2 numbers A and B which are between 1 and 10.

The program will then ask the user (your brother)

"What is the sum of A and B? The program will accept the

users answer (as input) and then either congratulate him

on the correct answer, or tell him to guess again.

The program will be halted when a negative number is

input!