while(cin>>ch):
In the above while loop, ch is a string type, and the cin>>ch bit is judged based on re-input every time the loop is entered. When the input is successful, the loop is entered , and conversely, when the input fails, the loop is not entered, so this kind of The loop is generally a loop input loop , and in each loop, the data input this time is processed.
continue & break:
Both are applied to loops, continue is to skip the current loop and go to the next loop, and break is to jump out of this loop directly.