# C Program to Generate Random Numbers2 min read

In this C program section, we will learn how to generate random numbers in C programming. Let us start with random numbers.

## What is Randon Number?

We can define Random as something that happens without any conscious decision. Similarly, a random number is a number that is chosen unpredictably or randomly from the set of numbers.

During programming or creating a project, you may come through scenarios to generate numbers such as in dice games, lottery systems, etc. Although, there are in-built functions in C which makes it easy.

• `rand()`
• `srand()`

## `rand()` function

`rand()` in c programming is a library function that generates random numbers within a range [0, RAND_MAX]. To use `rand()`, we need to provide a header file `<stdlib.h>`. The return type of `rand()` is a random integer type.

#### Program: Generate the random numbers using the rand() function in C.

Output:

`Random number:: 1804289383 Random number:: 846930886 Random number:: 1681692777 `

#### Program: Generate 4 random numbers using the rand() function in C.

Output 1:

`4 Random Numbers are: 1804289383 846930886 1681692777 1714636915 1957747793`

Output 2:

`4 Random Numbers are: 1804289383 846930886 1681692777 1714636915 1957747793`

No matter how many times you execute this program, it will return the same sequence of random numbers on every execution of the programming.

## `srand()` function

`srand()` is a library function that sets the starting value for producing a series of pseudo-random integers. A `srand()` function cannot be used without using a rand() function. The `srand()` function is used to set the seed of the rand function to a different starting point.

It is used in the following manner in the programmer:

`int srand(unsigned int seed) `

Seed is an integer value for the new sequence in pseudo-random numbers.

#### Program: Generate the random numbers using the srand() function in C.

Output:

`Enter how many numbers you want: 5 5 Random Numbers are: 55 70 60 17 50`

Again after second execution:

`Enter how many numbers you want: 5 5 Random Numbers are: 36 70 91 3 2`

Now you can see that the program returns series of different random number after every execution.

### String Pattern Programs in C

In this tutorial, we will write various C pattern programs for String. Before that, you may go through the following topics in C. for loop …

### Java Program to Find pair of Integers in Array whose sum is given Number

In this tutorial, we will write a program to find a pair of elements from an array whose sum equals a given number in java …

### Program to Print Diamond Alphabet Patterns in C

In this tutorial, we will learn to write a C program to print Diamond patterns using alphabets/characters. However, in this tutorial, we will create a …

### Half Diamond Pattern in C using Alphabets

In this tutorial, we will learn and code the half diamond alphabet patterns in C programming language. However, in this tutorial, we will create a …

### Half Pyramid of Alphabets in C

In this tutorial, we will learn and code alphabet patterns in C programming language specifically the Half pyramid of alphabets in C programming. However, in …

### Inverted Half Pyramid Pattern of Alphabets in C

In this tutorial, we will write a C program to print half Pyramid using alphabets/characters. Before that, you may go through the following topic in …