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Generating Random Integers

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Original post by nickwinters
Anyone know a Visual C++ 6.0 Library that generates random integers or floats?


int Rand = rand () % 10

this will random numbers between 0 and 9

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#include <cstdlib>
#include <ctime>

// ...

srand( unsigned (time(NULL)) );
int rNumber = rand() % 100;

You must include cstdlib to use the rand() function, yet the rand() function will return the same random numbers every time your program runs, as it uses the result of the last call to rand() to seed the next call. If you seed it with a value before its first use, then the random numbers it produces wont all be the same. You need to seed it with something that changes, though, else they will be the same every time you run your program. Something that is always changing is time, so you can seed it with time.

To seed rand(), you invoke the srand() function (cstdlib), which takes an argument of type unsigned int as the seed value. If you include ctime you can use the time() function. You can merely call it with NULL.

The rand() function returns a value between 0 and a compiler dependant number (defined as MAX_VALUE or something, but you don't need to worry about it). So you can do:
rand() % 100
to get a number between 0 and 100.

:::: Lektrix ::::
[ Google || ACCU || BarrysWorld || E-Mail Me ]

[edited by - Lektrix on February 2, 2003 10:25:34 AM]

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