Control flow

C++:

#include <iostream>

using namespace std;

int main()
{
    int x = 1;
    if(x > 0) 
    {
        cout << "Positive number" << endl;
    }
    else if(x < 0)
    {
        cout << "Negative number" << endl;
    }
    else
    {
        cout << "Zero" << endl;
    }

    for(int i = 0; i < 10; i++)
    {
        cout << i << "*" << i << "=" << i*i << endl;        
    }

    int t = 10;
    while(t < 100)
    {
        t += t/2;
    }
    cout << t << endl;

    t = 0;
    do 
    {
        cout << t << endl;
        t += 2;
    }while(t <= 10);

    int age = 15;
    if(age <= 12)
        cout << "A child" << endl;
    else if(age <= 19)
        cout << "A teenage at the age of " << age << endl;
    else
        cout << "An adult at the age of " << age << endl;
}

Rust :

fn main()
{
    let x = 1;
    if x > 0 
    {
        println!("Positive number");
    }
    else if x < 0 
    {
        println!("Negative number");
    }
    else
    {
        println!("Zero");
    }

    for i in 0..10
    {
        println!("{}*{}={}", i, i, i*i);
    }

    let mut t = 10;
    while t < 100 
    {
        t += t/2;
    }
    println!("{}", t);

    t = 0;
    loop 
    {
        println!("{}", t);
        t += 2;
        if !(t <= 10) 
        {
            break;
        }
    }

    let age = 15;
    match age
    {
        0...12  => println!("A child"),
        n @ 13...19 => println!("A teenage at the age of {}", n),
        n      => println!("An adult at the age of {}", n)
    }
}

Most of flow control syntax in C++ and Rust are similar, besides, Rust does not require parentheses in condition clauses. Rust match syntax is more flexible than C++ switch/case syntax (which is not shown in this example).