Examples

This page contains practical examples demonstrating various GLaDOS features.

Basic Programs

Hello World (Simple Return)

int main() {
    return 42;
}

Output: 42

Simple Addition

int add(int a, int b) {
    return a + b;
}

int main() {
    return add(5, 3);
}

Output: 8

Variable Declaration and Assignment

int main() {
    int x = 10;
    int y = 20;
    int z = x + y;
    return z;
}

Output: 30

Control Flow Examples

If-Else Statement

int max(int a, int b) {
    if (a > b) {
        return a;
    } else {
        return b;
    }
}

int main() {
    int result = max(10, 20);
    return result;
}

Output: 20

Nested If Statements

int abs(int x) {
    if (x < 0) {
        return -x;
    } else {
        return x;
    }
}

int main() {
    return abs(-15);
}

Output: 15

While Loop

int sum_to_n(int n) {
    int sum = 0;
    int i = 1;

    while (i <= n) {
        sum = sum + i;
        i = i + 1;
    }
    return sum;
}

int main() {
    return sum_to_n(10);  // 1+2+3+...+10
}

Output: 55

Recursive Functions

Factorial

int factorial(int n) {
    if (n <= 1) {
        return 1;
    }
    return n * factorial(n - 1);
}

int main() {
    int result = factorial(5);
    return result;
}

Output: 120 (5! = 5×4×3×2×1)

Fibonacci

int fib(int n) {
    if (n <= 1) {
        return n;
    }
    return fib(n - 1) + fib(n - 2);
}

int main() {
    return fib(10);
}

Output: 55

Power Function

int power(int base, int exp) {
    if (exp == 0) {
        return 1;
    }
    return base * power(base, exp - 1);
}

int main() {
    return power(2, 8);  // 2^8
}

Output: 256

Boolean Logic

Comparison Functions

bool isPositive(int x) {
    return x > 0;
}

bool isNegative(int x) {
    return x < 0;
}

int main() {
    bool result = isPositive(5);
    if (result) {
        return 1;
    }
    return 0;
}

Output: 1

Range Checking

bool isInRange(int x, int low, int high) {
    return (x >= low) && (x <= high);
}

int main() {
    bool result = isInRange(5, 1, 10);
    if (result) {
        return 1;
    }
    return 0;
}

Output: 1

Logical Operations

int main() {
    bool a = 5 < 10;       // true
    bool b = 10 == 10;     // true
    bool c = a && b;       // true

    if (c) {
        return 1;
    }
    return 0;
}

Output: 1

Function Composition

Nested Function Calls

int double(int x) {
    return x * 2;
}

int quadruple(int x) {
    return double(double(x));
}

int main() {
    return quadruple(5);
}

Output: 20

Helper Functions

int square(int x) {
    return x * x;
}

int sumOfSquares(int a, int b) {
    return square(a) + square(b);
}

int main() {
    return sumOfSquares(3, 4);  // 3² + 4² = 9 + 16
}

Output: 25

Iterative vs Recursive

Factorial (Iterative)

int factorial_iter(int n) {
    int result = 1;
    while (n > 0) {
        result = result * n;
        n = n - 1;
    }
    return result;
}

int main() {
    return factorial_iter(5);
}

Output: 120

Factorial (Recursive)

int factorial_rec(int n) {
    if (n <= 1) {
        return 1;
    }
    return n * factorial_rec(n - 1);
}

int main() {
    return factorial_rec(5);
}

Output: 120

Advanced Examples

Greatest Common Divisor (GCD)

int gcd(int a, int b) {
    while (b != 0) {
        int temp = b;
        b = a - (a / b) * b;  // a mod b
        a = temp;
    }
    return a;
}

int main() {
    return gcd(48, 18);
}

Output: 6

Count Digits

int countDigits(int n) {
    int count = 0;

    if (n == 0) {
        return 1;
    }

    while (n != 0) {
        n = n / 10;
        count = count + 1;
    }
    return count;
}

int main() {
    return countDigits(12345);
}

Output: 5

Reverse Number

int reverse(int n) {
    int reversed = 0;

    while (n != 0) {
        int digit = n - (n / 10) * 10;  // n mod 10
        reversed = reversed * 10 + digit;
        n = n / 10;
    }
    return reversed;
}

int main() {
    return reverse(12345);
}

Output: 54321

Expression Statements

Function calls can be used as statements (result discarded):

int print(int x) {
    return x;  // Pretend this prints
}

int main() {
    print(42);  // Expression statement
    print(100);
    return 0;
}

Output: 0