fn main() {
   let mut x = vec!["this","is","a","sentence"];
   for i in 0..x.len(){
       print!("{} ",x[i]);
   }
   println!();
   x.insert(1,"line");
   for i in 0..x.len(){
       print!("{} ",x[i]);
   }
   println!();
   x.insert(2,"contains");
   for i in 0..x.len(){
       print!("{} ",x[i]);
   }
   println!();
   x.remove(3);
   for i in 0..x.len(){
       print!("{} ",x[i]);
   }
   println!();
   x.push("about rust");
   for i in 0..x.len(){
       print!("{} ",x[i]);
   }
   println!();
   x.pop();
   for i in 0..x.len(){
       print!("{} ",x[i]);
   }
   println!();
   
}