What is the difference between ios::out or ios::trunc

Question

Hey programmer i really dont understand what is the purpose of ios::trunc and one more thing why i cant use it like
fstream ptr;
ptr.open("ram.txt",ios::trunc);

Answer 1

ios::out writes over the original content of a file, and if what you put in a file is bigger than its contents, contents will be completely removed....

Answer 2

ios::trunc means that if the file is opened for output operations and it already existed, its previous content is deleted and replaced by the new one.

Answer 3

But ios::out starts to write from beginning without deleting previous content.

Also ios::app could be used to append to the file

Answer 4

Aleksei Radchenkov thankyou now i get it.😊

Answer 5

Aleksei Radchenkov thanks bro but the issue is sometimes ios::out also delete previous content and i dont understand why is happening is there any reason behind it