2. Characters

• We can read individual characters:

  • Using formatted input:

    
        char ch;
        while ( cin >> ch ) {
            // read into ch, skipping whitespace characters
            if ( isalpha( ch ) ) {
                // do something
            }
        }
    
    

  • Using unformatted input:

    
        #include <iostream>
        #include <cctype>
    
        char ch;
        while ( cin.get( ch ) ) {
            if ( isspace( ch ) ) {
                // if ch is whitespace
                // do nothing (i.e. skip whitespace)
            }
            if ( isdigit( ch ) ) {
                // read a number
            }
            else if ( isalpha( ch ) ) {
                // read an identifier
            }
            else {
                // deal with operators
            }
        }
    
    

• A complete example: chapter_11_6.cpp (download)