Sometimes one side would suicidally charge the other with bayonets. On foot or cavalry. Later, cannons were used as fire support.
Generally, this was though of as sportsmanlike by the nobles that waged these wars.
The practice eventually began to wane when people realized that doing this was fucking insane. And basically outright stopped once World War I rolled around.
Not to mention, even if you survived getting shot, you'd probably get a limb amputated, without anesthetics, at best. Slow painful death at worst.
You probably had a better chance at surviving Russian Roulette. A Gentlemans' War was more like a gamble with the Grim Reaper.