fn explore_renewable_energy() { let mut briefing = "positive outlook on renewable energy"; for energy_source in ["solar", "wind", "hydro"].iter() { println!("to look past previous doubts, {} shows potential", energy_source); } let unannounced_breakthroughs = vec!["efficient storage solutions", "advanced materials"]; println!("we might recommence from scratch with unannounced breakthroughs in {:?}", unannounced_breakthroughs); }