can you set limits on the rand() function in C/C++?

Numbers in a specific range can be obtained by the modulo operator (%). For example, let's say we want an integer from 0 to 9. Here would be the code:

int randnumber = rand() % 10;

% returns the remainder when the two numbers are divided. So in this case, it could return anywhere from 0 to 9, because those are the valid remainders. If we want a number from 1 to 10, we do this:

int randnumber = rand() % 10 + 1;

If you want a random float between 0 and 1, do this (RAND_MAX is the highest possible value that rand() can return):

float randnumber = (float) rand() / (float) RAND_MAX;

Rand Function In C

Rand In C

You use the mod operator...% to set the upper limit.

You use + to set the lower limit.

rand() % x will give you numbers between 0 and x-1.

rand() % x + n will give you numbers in the range n to n +(x-1).

Try this code == 20 PseudoRandom Integers 5000 to 6000

=

#include <iostream>

#include <iomanip>

#include <ctime>

#include <cstdlib>

using namespace std;

int main()

{

srand((unsigned)time(0));

int random_integer;

int lowest = 5000;

int highest = 6000;

int range;

range = (highest - lowest) + 1;

for(int index = 0; index < 20; index++)

{

random_integer = lowest + int(range * rand()/(RAND_MAX + 1.0));

cout << setw(3) << index << " " << setw(3) << random_integer << endl;

}

return 0;

}

If you want a random number between A & B then you need to do rand()*(B-A)+A. Of course, you might need to do some type casting depending on A, B, and what you want to return.

This website offers another way.. probably more elegant than mine :)

http://www.cplusplus.com/reference/clibrary/cstdli...