Final answer:
To append a character to a string in C++, add the line 'inputString += addChar;' to concatenate the input character to the input string before the output statement.
Step-by-step explanation:
The question pertains to Programming, specifically in appending a character to a string using C++. This task involves reading user input from the console to append a character to a given string using standard input-output streams provided by the C++ library functions.
To answer the question, the code snippet provided will be modified to include an additional line of code within the main function:
inputString += addChar;
This line of code will concatenate the character addChar to the end of the inputString. The program then outputs the modified string to the console.