JavaScript: Generate a random integer

JavaScript Math: Exercise-4 with Solution

Generate a Random Integer

Write a JavaScript function to generate a random integer.

Test Data :
console.log(rand(20,1));
console.log(rand(1,10));
console.log(rand(6));
console.log(rand());
15
5
1
0

Visual Presentation:

Sample Solution:

JavaScript Code:

// Define a function named rand that generates a random integer between the specified minimum and maximum values.
rand = function(min, max) {
    // If both minimum and maximum values are not provided, return 0.
    if (min == null && max == null)
        return 0;    

    // If only one value is provided, treat it as the maximum and set minimum to 0.
    if (max == null) {
        max = min;
        min = 0;
    }
    // Generate a random integer between min (inclusive) and max (inclusive).
    return min + Math.floor(Math.random() * (max - min + 1));
};

// Output a random integer between 20 and 1 (inclusive) to the console.
console.log(rand(20, 1));
// Output a random integer between 1 and 10 (inclusive) to the console.
console.log(rand(1, 10));
// Output a random integer between 6 and 0 (inclusive) to the console.
console.log(rand(6));
// Output a random integer between 0 and 0 (inclusive) to the console.
console.log(rand());
 

Output:

4
1
2
0

Explanation:

In the exercise above,

• The code defines a function called "rand()" which generates a random integer within a specified range.
• The "rand()" function takes two parameters: 'min' and 'max', representing the minimum and maximum values of the range.
• Inside the function:
• If both 'min' and 'max' parameters are not provided (null), it returns 0.
• If only one parameter is provided (which is treated as the maximum value), it sets the minimum value to 0.
• It then generates a random integer between 'min' (inclusive) and 'max' (inclusive) using "Math.random()" and some arithmetic operations.

Flowchart:

Live Demo:

See the Pen javascript-math-exercise-4 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript function that generates a random integer within a specified range and ensures uniform distribution.
• Write a JavaScript function that generates a random integer using Math.random() and rounds the result using bitwise operators.
• Write a JavaScript function that accepts optional minimum and maximum parameters to generate a random integer, using default values when omitted.
• Write a JavaScript function that repeatedly generates random integers until a prime number is produced.

Go to:

• JavaScript Math and Numbers Exercises Home ↩
• JavaScript Exercises Home ↩

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