Why Does My C rand() Function Keep Returning the Same Value, and How Do I Fix It Using srand()?

srand() Function Behavior Within a Function

While working with the rand() function in C , one may encounter an issue where calling the function multiple times within the same function consistently yields the same value. To resolve this issue, it is essential to understand the behavior of the srand() function.

What is srand() and Why Does It Matter?

The srand() function initializes the random number generator. When repeatedly calling the rand() function without re-initializing it with srand(), it continues producing subsequent numbers from the same seed, resulting in predictable outcomes.

Solution to Fix Randomness

To ensure true randomness, the srand() function should be called only once at the beginning of the program, rather than within a specific function. By doing so, the seed is set only once, allowing the rand() function to generate a truly random sequence through subsequent calls.

Applying the Solution

In the provided code snippet, the issue lies within the PullOne() function. The srand() function is being called before each invocation of rand(), leading to a predictable sequence and repeated results. To correct this, move the call to srand() to the start of the main function:

int main() {
    std::srand(time(0));

    string pull_1, pull_2, pull_3;
    pull_1 = PullOne();
    pull_2 = PullOne();
    pull_3 = PullOne();

    return 0;
}

By applying this modification, the rand() function will produce distinct values for pull_1, pull_2, and pull_3.

The above is the detailed content of Why Does My C rand() Function Keep Returning the Same Value, and How Do I Fix It Using srand()?. For more information, please follow other related articles on the PHP Chinese website!