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Derek Snider edited this page May 19, 2026 · 1 revision

Functions

Basic functions

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

void greet(string name) {
    cout << "Hello, " << name << endl;
}

int main() {
    int result = add(10, 20);
    greet("World");
    return 0;
}

Multiple return values

Go-style multiple returns using comma-separated values:

int divmod(int a, int b) {
    return a / b, a % b;
}

int main() {
    int q, r;
    q, r = divmod(17, 5);
    cout << "quotient: " << q << ", remainder: " << r << endl;
    return 0;
}

The := operator also works for multiple returns with type inference:

q, r := divmod(17, 5);

Currently works with numeric types only. Always use braces around multi-return if/else blocks.

Function pointers

Store a function's address and call through it:

void greet(string name) {
    cout << "Hi " << name << endl;
}

int main() {
    auto fn = greet;
    fn("World");          // calls greet("World")
    return 0;
}

auto infers the function pointer type from the assigned function.

Lambda expressions

Anonymous inline functions:

// void lambda
auto print = [](string s) { cout << s << endl; };

// typed-return lambda (return type inside [])
auto add = [int](int a, int b) { return a + b; };

int main() {
    print("hello");
    int result = add(10, 20);
    cout << result << endl;    // 30
    return 0;
}

Return type goes inside []: [int], [string], or [] for void.

Class methods

Classes support methods with an implicit this pointer:

class Counter {
    int count;

    void inc() {
        count = count + 1;
    }

    int get() {
        return count;
    }
};

int main() {
    Counter c;
    c.count = 0;
    c.inc();
    c.inc();
    cout << c.get() << endl;   // 2
    return 0;
}

See Structs & Classes for more.

Command-line arguments

int main(int argc, char **argv) {
    printf("Script: %s\n", argv[0]);
    for (int i = 1; i < argc; i++)
        puts(argv[i]);
    return 0;
}

Run: madc script.mad arg1 arg2 arg3

Both int main() and int main(int argc, char **argv) are supported.

Built-in functions

Function Description
puts(s) Print C-string + newline
putchar(c) Print a character
puti(i) Print integer
strlen(str) String length
stoi(str) String to integer
stod(str) String to double
to_string(result, int) Integer to string
system(cmd) Run shell command
getenv(result, name) Get environment variable
setenv(name, value) Set environment variable

Plus all namespace functions and anything available via dlsym (libc functions work automatically).

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