randInt() in CodeCraft

We use random integers a lot in CodeCraft. The function we defined randInt(min, max) is used to generate random integers.

Example 1: Make an array of random integers:

let nums = [];

for (let i = 0; i < 5; i++) {
    nums.push(randInt(1,20));
}

console.log(nums);

Each time you run the above code, you should get a different set of numbers such as:

[11, 13, 8, 10, 10]
[16, 9, 16, 18, 8]

Example 2: build blocks at random locations with random material

Generating blocks at random locations would be easy with randInt(). For example, if you use randInt(1, 20) as the input value for the x coordinate, the block will show up at random x locations from 1 to 20.

To build blocks with random materials, let's use function block_m(x, y, z, m) where m is a number indicating the materials.

# random x, y, z, m
# 10 blocks with different materials at different locations
for (let i = 0; i < 10; i++) {
    block_m(randInt(1, 20), randInt(1, 20), randInt(-20, -10), randInt(1, 88) );
}

Each time you run the above code you will get a set of 10 different blocks at different locations.

Example 3: Random columns

You can also generate columns of random materials with random heights. Let's use the function column_m():

for (let i = 0; i < 10; i++) {
    column_m(i, -10, randInt(1, 20), randInt(1, 16));
}

Example 3 generated ten random colored columns with random heights.

Run all the programs a few times and see what you get! Can you explain why some of these columns below have different color segments?

Example 4: random way to go

In this example we will grow a random plant. A random integer is used to control which way it grows into. 0: left, 1: right, 2: up.

// random direction
let x = 0;
let y = 1;

for (let i = 0; i < 20; i++) { 
    block(x, y, -30, "box_brown");

    let direction = randInt(0, 3);

    if (direction == 0) {
        x -= 1;
    }
    else if (direction == 1) {
        x += 1;
    }
    else {
        y += 1;
    }
}

Run the code three times, each time using a different initial x value: -5, 0, 5. We get 3 random "plants":