Question

Suppose that age is an int variable, ch is a char variable, and name is a string variable. What are the values of age and name after the following input statements execute: cin >> age; cin.get(ch); getline(cin, name); if the input is: a. 23 Lance Grant b. 23 Lance Grant

Short answer

For both inputs, age = 23 and name = "Lance Grant".

Step-by-step solution

Read the First Input Value (age)

The statement `cin >> age;` reads the first integer from the input. In both input cases, "23" will be read into the variable `age`. After executing this statement, `age` holds the value 23.

Read the Next Character (ch)

The statement `cin.get(ch);` reads the next character from the input stream. For input (a), it reads the space character following "23". For input (b), it reads the newline character after "23". The variable `ch` will store whatever character comes immediately after the integer in the input stream.

Read the Remaining Input Line (name)

The `getline(cin, name);` function reads the rest of the input line until a newline character is encountered. In input (a), it captures "Lance Grant" after consuming the initial space character during the `ch` read operation. In input (b), it captures "Lance Grant" which starts after the newline character, so `name` is the same for both inputs.

Key concepts

Using 'cin' for Input in C++

In C++, `cin` is a standard input stream used for reading data from the user. Its main purpose is to store user input directly into the variables provided. For example, when we use `cin >> age;`, it reads the next available integer from the input and assigns it to the variable `age`. After executing this line, the whitespace or newline following the entered number remains in the input buffer. Key points about using `cin` include:

• It's typically used for basic data types such as `int`, `char`, or `double`.
• Whitespace acts as a delimiter, so `cin` stops reading once it encounters a space.
• If reading a string that consists of multiple words, `cin` will only capture the first word.

When using `cin` for inputs, keep in mind that it might leave unwanted characters such as spaces or newline characters in the input buffer, which can affect the subsequent input operations.

Reading Strings with 'getline'

The `getline` function in C++ is particularly useful for handling string input that might include spaces. Unlike `cin`, `getline` reads an entire line from the input stream and stores it in a string variable until a newline character is encountered. This makes it ideal for inputs that are sentences or names. When using `getline`, consider:

• It reads everything on the line, including spaces, until it reaches a newline.
• Once invoked, it clears any previous data in the string variable and replaces it with the input data.
• In scenarios where it's preceded by `cin`, unwanted characters (like newline or spaces) may need to be handled to avoid skipping input.

In the context of the exercise, `getline(cin, name);` effectively reads the remaining input from the stream, capturing names like "Lance Grant" entirely in one go.

Character Reading with 'cin.get()'

The `cin.get(char& ch)` function is used in C++ to read single characters from the input stream. This function is especially handy when you want to process input character by character rather than line by line. Here are some characteristics of `cin.get()`:

• It reads and stores exactly one character from the input stream, including whitespaces, like spaces and newlines.
• After reading a character, it advances to the next character in the input buffer.
• Using `cin.get(ch);` after `cin >> age;` is why the char variable captures the space or newline after the number input.

Although less commonly used for typical programming tasks, `cin.get()` is perfect for cases where you need precise control over input processing, such as when parsing individual characters or handling specific delimiters.