How Can I Generate Random Floating-Point Numbers in C ?

Generating Random Floating-Point Numbers in C

In C , the rand() function serves as a reliable tool for creating pseudo-random numbers. By combining it with RAND_MAX and performing simple mathematical operations, you can generate random floats within specified intervals. For recreational programs and educational purposes, this approach suffices. However, if your requirement demands genuinely random numbers with normal distribution, consider implementing more sophisticated techniques.

Generating Floats from 0.0 to 1.0

To obtain a random float between 0.0 and 1.0 (inclusive), employ the following formula:

float r = static_cast<float>(rand()) / static_cast<float>(RAND_MAX);

Generating Floats within an Arbitrary Range

For generating a float within the range [0.0, X], use the following formula:

float r2 = static_cast<float>(rand()) / (static_cast<float>(RAND_MAX) / X);

Generating Floats within a Custom Range

To generate a float within the range [LO, HI], utilize the following formula:

float r3 = LO + static_cast<float>(rand()) / (static_cast<float>(RAND_MAX) / (HI - LO));

Initializing the Random Number Generator

Before employing rand(), it is crucial to initialize the random number generator by calling srand(). This initialization should occur only once during the program's execution, not with each call to rand(). A common practice involves:

srand(static_cast<unsigned>(time(0)));

Header File Inclusions

Note the following header file inclusions are necessary:

• for calling rand() and srand()
• for calling time()

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