Why Does My Random Number Generator Keep Producing the Same Sequence?

Random Number Generator Resetting to the Same Sequence

Each time you execute a program that utilizes the rand() function, you might notice it produces identical sequences of numbers. This occurs because the random number generator's seed is not initialized.

To produce more unpredictable results, set the random number generator's seed using srand((unsigned int)time(NULL)). This function employs the current time as the seed, providing more variety in the generated numbers. Consider the following code:

#include <iostream>
#include <cstdlib>
#include <ctime>

using namespace std;

int random(int low, int high) {
    if (low > high)
        return high;
    return low + (rand() % (high - low + 1));
}

int main() {
    srand((unsigned int)time(NULL));
    cout << random(2, 5) << endl;
    return 0;
}

The rand() function is not inherently random, but rather utilizes a mathematical transformation. Each call to rand() generates a result based on the seed or previous random numbers, creating a predictable sequence without explicit initialization. By using srand with a truly random value (like the current time), the random number generator's state becomes more unpredictable, leading to more varied results.

For further insights, refer to these resources:

• http://www.dreamincode.net/forums/topic/24225-random-number-generation-102/
• http://www.dreamincode.net/forums/topic/29294-making-pseudo-random-number-generators-more-random/

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