- len
- capacity
- macro_rules
Capacity of string
examples/strings/capacity/src/main.rs
macro_rules! prt { ($var:expr) => { println!( "{:2} {:2} {:?}", $var.len(), $var.capacity(), $var, ); }; } fn main() { let mut text = String::new(); prt!(text); text.push('A'); prt!(text); text.push_str(" black "); prt!(text); text.push_str("cat"); prt!(text); text.push_str(" climebed"); prt!(text); }
0 0 "" 1 8 "A" 8 8 "A black " 11 16 "A black cat" 20 32 "A black cat climebed"