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if

#![allow(unused)]
fn main() {
if number % 4 == 0 {
    println!("number is divisible by 4");
} else if number % 3 == 0 {
    println!("number is divisible by 3");
} else if number % 2 == 0 {
    println!("number is divisible by 2");
} else {
    println!("number is not divisible by 4, 3, or 2");
}

    
// 类似三元运算
let number = if condition { 5 } else { "six" };
}

loop 死循环

#![allow(unused)]
fn main() {
loop {
 println!("again!");
}
 
// 返回结果
let result = loop {
   counter += 1;

   if counter == 10 {
       break counter * 2; // 高级感
   }
};
}

while

#![allow(unused)]
fn main() {
while number != 0 {
  println!("{}!", number);

  number -= 1;
}
}

for

#![allow(unused)]
fn main() {
for element in a {
    println!("the value is: {}", element);
}
    
    
// 倒着循环
for number in (1..4).rev() {  // 又是高级感
    println!("{}!", number);
}

}