What is the difference between целый, все, and весь?
Целый - the whole. Also, it has a meaning "without damages". For example, "ты цел?" = "are you alright?", "чашка, упавшая со стола, целая" = "the cup that fell from the table is ok"
Все (plural) - "All", "all these ones". E.g. "Everyone put your hands up" = "Поднимите все руки"
Весь (masculine, singular, вся = feminine, singular) - the whole. It has a meaning "all parts together", e.g. "I have slept the whole day" = "я проспал весь день", "я потерял всю коллекцию марок" = "I have lost the entire collection of stamps".
"Поднимите все руки" = Put all your hands up
"Все, поднимите руки" = Everyone put your hands up
Because все and весь are different forms of one an the same word (plural and singular masculine respectively), there are two words you a interested in the difference between: целый and весь.
Basically, they are like all and whole in English: they mean pretty much the same thing, which is "entire", but are different in nuances of meaning and application.
When @1Pozin2 says, "Я съел весь арбуз," it means that he's eaten it all (all its pieces) and left nothing for us.
But when he says, "Я съел целый арбуз," I'd go like, "Everybody take your cover, Pozin can explode any moment now!" because watermelons tend to be big and eating an entire one is challenging as being too much for a single person's stomach.
- весь is more like all, meaning all of the parts the entire thing consists of.
- целый is more like whole meaning the entire thing altogether as a whole.
This difference enables secondary meanings of:
все as "everyone"
Весь класс смеялся. - All the group (literally, everyone in that group) was laughing.
целый as "not broken"
Чашка упала на пол, но осталась целой - The cup fell down on the floor but did not break (literally, remained whole).
When you don't need to emphasize these nuances, they are interchangeable:
я проспал весь день = я проспал целый день.
And yet "весь" is more emotionally neutral than "целый", and for that is preferable in non-emphatic sentences.
Я съел целый арбуз. Я принёс домой целый арбуз из магазина. На тарелке был кусок арбуза и я съел весь этот арбуз. Все = everything. Я съел все, что было на столе. But целый/весь кусок хлеба, целый/весь день.
"все" is a plural, "весь" is a singular. Its a another forms of one word. "целый" means "not breaked", "весь" means "all the parts [do something]" "целая коробка" means "not-breaked box", or "full box". "вся коробка" means what all parts of box should be do something, and no one of them would not be "lazy" or "not-used".