Repeating Tasks — For and While Loops

Loops let you run code multiple times without writing it over and over. AdeshLang has two main loop types.

The for Loop — Count-Based

Use for when you know how many times to repeat.

Range Loop

// Count from 0 to 4 (5 times)
for i in 0..5 {
    print("Iteration:", i);
}

Output:

Iteration: 0
Iteration: 1
Iteration: 2
Iteration: 3
Iteration: 4

Range Syntax

Syntax	Meaning	Values
0..5	0 to 4 (exclusive end)	0, 1, 2, 3, 4
1..6	1 to 5 (exclusive end)	1, 2, 3, 4, 5
0..=5	0 to 5 (inclusive end)	0, 1, 2, 3, 4, 5

// Inclusive range
for i in 1..=5 {
    print(i);
}
// Output: 1 2 3 4 5

Loop Over Arrays

let fruits = ["apple", "banana", "cherry"];

for fruit in fruits {
    print("I like", fruit);
}

Output:

I like apple
I like banana
I like cherry

Loop with Index

let names = ["Alice", "Bob", "Charlie"];

for i in 0..len(names) {
    print(i, ":", names[i]);
}

Output:

0 : Alice
1 : Bob
2 : Charlie

The while Loop — Condition-Based

Use while when you repeat until a condition becomes false.

let count = 0;

while (count < 5) {
    print("Count:", count);
    count = count + 1;    // Must update!
}

Output:

Count: 0
Count: 1
Count: 2
Count: 3
Count: 4

⚠️ Warning: Always update the condition variable, or you'll create an infinite loop!

Loop Control: break and continue

break — Exit Loop Early

for i in 0..10 {
    if (i == 5) {
        print("Stopping at", i);
        break;    // Exit loop completely
    }
    print(i);
}

Output:

0
1
2
3
4
Stopping at 5

continue — Skip to Next Iteration

for i in 0..5 {
    if (i == 2) {
        continue;    // Skip rest of this iteration
    }
    print(i);
}

Output:

0
1
3
4

Practical Examples

Example 1: Sum Array Elements

let numbers = [10, 20, 30, 40, 50];
let sum = 0;

for n in numbers {
    sum = sum + n;
}

print("Sum:", sum);    // Sum: 150

Example 2: Find Maximum

let scores = [85, 92, 78, 96, 88];
let max = scores[0];

for score in scores {
    if (score > max) {
        max = score;
    }
}

print("Highest:", max);    // Highest: 96

Example 3: Countdown

let seconds = 10;

while (seconds > 0) {
    print(seconds, "...");
    seconds = seconds - 1;
}

print("🚀 Blast off!");

Example 4: Number Guessing Game (Simulated)

let secret = 7;
let guess = 0;
let attempts = 0;
let max_attempts = 3;

while (guess != secret && attempts < max_attempts) {
    // Simulated guesses
    if (attempts == 0) guess = 5;
    elif (attempts == 1) guess = 8;
    else guess = 7;
    
    attempts = attempts + 1;
    print("Attempt", attempts, ": You guessed", guess);
    
    if (guess < secret) print("Too low!");
    elif (guess > secret) print("Too high!");
}

if (guess == secret) {
    print("Correct! You won in", attempts, "attempts!");
} else {
    print("Game over! The number was", secret);
}

Nested Loops

Loops inside loops:

// Multiplication table 1-3
for i in 1..=3 {
    for j in 1..=3 {
        print(i, "x", j, "=", i * j);
    }
    print("---");
}

Output:

1 x 1 = 1
1 x 2 = 2
1 x 3 = 3
---
2 x 1 = 2
2 x 2 = 4
2 x 3 = 6
---
3 x 1 = 3
3 x 2 = 6
3 x 3 = 9
---

for vs while — When to Use Which?

Situation	Use
Known number of iterations	for
Iterating over array/collection	for
Counting with range	for
Unknown iterations, condition-based	while
Waiting for user input	while
Game loop	while

Infinite Loop (Intentional)

// Use break to exit
while (true) {
    let input = "quit";    // Simulated
    if (input == "quit") break;
    print("Processing:", input);
}

Quick Reference

Task	Code
Range loop	for i in 0..n { }
Inclusive range	for i in 0..=n { }
Array loop	for item in array { }
While loop	while (condition) { }
Exit loop	break;
Skip iteration	continue;

Practice Exercise

Create exercise.adesh:

// 1. Print even numbers 1-20
print("Even numbers:");
for i in 1..=20 {
    if (i % 2 == 0) {
        print(i);
    }
}

// 2. Sum 1 to 100
let total = 0;
for i in 1..=100 {
    total = total + i;
}
print("Sum 1-100:", total);    // 5050

// 3. Factorial with while
let n = 5;
let factorial = 1;
let i = 1;
while (i <= n) {
    factorial = factorial * i;
    i = i + 1;
}
print("5! =", factorial);    // 120

// 4. Print pattern
print("Pattern:");
for row in 1..=5 {
    let line = "";
    for col in 1..=row {
        line = line + "*";
    }
    print(line);
}

Expected Output:

Even numbers:
2
4
6
...
20
Sum 1-100: 5050
5! = 120
Pattern:
*
**
***
****
*****

Summary

✅ You learned:

• for i in 0..5 { } — count from 0 to 4
• for i in 1..=5 { } — count from 1 to 5
• for item in array { } — iterate array elements
• while (condition) { } — repeat while true
• break — exit loop immediately
• continue — skip to next iteration
• Nested loops for grids/patterns

Next Step

Now let's organize code into functions! Continue to Functions →