Number of Characters Escaped

Problem Statement

Number of Characters Escaped Problem Description You are given a string expression made up of lowercase English letters and the characters # (ASCII value 35) and ! (ASCII value 33). Determine how many characters in it are escaped . A character is escaped if all of the following hold: it is a lowercase English letter, the character immediately before it is ! , and both the letter and that ! lie between the same pair of # characters. The # characters are never nested, and every opening # has a closing # . Reading from left to right, the 1st and 2nd # form a pair, the 3rd and 4th # form the next pair, and so on. (inferred -- the source states only that # characters are not nested and always closed; pairing them in order is the only reading consistent with its samples.) Complete the function numberOfCharactersEscaped(expression) , which returns the number of escaped characters. Input Format Read from standard input. expression The first and only line contains the string expression . It con