# Random Function in C

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In C programming, the **rand() function **is commonly used to generate random numbers within a specified range.

To use this function effectively, it's important to understand its syntax, behavior, and the necessity of using** srand() **to seed the random number generator.

##
**rand() Function **

The** rand() function** is a standard library function in C that generates a pseudo-random integer in the range** [0, RAND_MAX]**.

It's defined in the **header** **file**.

One thing to note about **rand()** is that it doesn't produce truly random numbers; rather, it generates numbers based on a **deterministic algorithm**.

**Syntax of rand() Function:**

int rand(void);

**Return Value:
**

The** rand()** function returns a random integer between** 0 **and **RAND_MAX**.

**RAND_MAX:
**

**RAND_MAX **is a predefined **symbolic constant** in the C standard library.

It's declared in the ** header file** and represents the maximum value that can be returned by the rand() function.

Its value is **implementation-defined **but is at least** 32767**.

##
**srand() Function **

The **srand() function** initializes the random number generator with a seed value, ensuring that the subsequent numbers generated by rand() will be different each time the program is run.

By providing a seed value to** srand()**, we can initialize the random number generator to produce different sequences of random numbers.

**Syntax for srand() Function
**

void srand(unsigned int seed);

**seed:
**

The seed value sets the initial state of the** random number generator**, determining the sequence of random numbers produced by subsequent calls to **rand()**.

Typically, **time(NULL)** is used as the seed to ensure different sequences of random numbers each time the program runs.

**Example:**

// program that demonstrates how to generate a random number using therand()function and seed it usingsrand()#include<stdio.h>#include<stdlib.h> #include<math.h> int main() { int randomNumber; // Seed the random number generator srand(time(NULL)); // Generate a random number between 0 and 9 randomNumber = rand() % 10; printf("Random Number: %d\n", randomNumber); return 0; }

**Output:
**

Random Number: 6

If you don't seed the random number generator using **srand()**, the **rand()** function will produce the same sequence of numbers every time you run the program.

By using **srand(time(NULL))**, you can ensure that the random number generator is seeded with a different value each time the program is executed, thus producing different sequences of random numbers.

Understanding and utilizing the **rand() **and **srand() functions** correctly can add randomness and unpredictability to your C programs, making them more versatile and interesting.

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