Write a program that generates a random number within a specified range [L, R]. The program should take two integers, L and R, as input and output a random number between L and R (inclusive).
Examples:
Input: L = 10, R = 20
Output: 15Input: L = -5, R = 5
Output: 3
Approach: To solve the problem, follow the below idea:
We can generate a random number in the range [L, R] by finding how many numbers are there between L to R by the formula: diff = (R – L + 1). Now, we can generate a random number and modulo the random number by diff and add the remainder to L to get a random number between L to R.
Step-by-step algorithm:
- Find the difference between L to R by (R – L + 1).
- Now, generate a random number and modulo it by the above difference.
- Scale and shift the random number by adding the remainder to L to fit within the specified range [L, R].
Below is the implementation of the algorithm:
#include <cstdlib> #include <ctime> #include <iostream> using namespace std;
int main()
{ int L = 10, R = 20;
srand ( time (NULL));
int random_number = L + rand () % (R - L + 1);
cout << random_number << endl;
return 0;
} |
#include <stdio.h> #include <stdlib.h> #include <time.h> int main()
{ int L = 10, R = 20;
srand ( time (NULL));
int random_number = L + rand () % (R - L + 1);
printf ( "%d\n" , random_number);
return 0;
} |
import java.util.Scanner;
public class RandomNumberGenerator {
public static void main(String[] args) {
int L = 10 ;
int R = 20 ;
int random_number = L + ( int ) (Math.random() * (R - L + 1 ));
System.out.println(random_number);
}
} |
import random
L, R = 10 , 20
random_number = random.randint(L, R)
print (random_number)
|
using System;
class Program
{ static void Main()
{
int L = 10;
int R = 20;
Random rand = new Random();
int random_number = rand.Next(L, R + 1);
Console.WriteLine(random_number);
}
} |
let L = 10 let R = 20 let random_number = Math.floor(Math.random() * (R - L + 1)) + L; console.log(random_number); |
15
Time Complexity: O(1), as it takes constant time to generate a random number.
Auxiliary Space: O(1)