Strip Blank Lines

Write a function int stripBlankLines(const string& filename) that removes every blank line from a text file and returns how many lines were removed. A blank line is a line with no characters at all.

Read all lines with getline, keep the non-blank ones in a vector<string>, then reopen the file in ios::out | ios::trunc mode and write the kept lines back, each followed by a newline.

The test prints the returned count on its own line and then every line of the file. For a file whose four lines are a, an empty line, b, and another empty line it prints the output shown in Expected Output.

Do NOT write a main function.