Question

Write a program that separately inputs a first name and a last name and concatenates the two into a new string.

Short answer

Input two strings, concatenate them, and print the result.

Step-by-step solution

Initialize Input Variables

Start by declaring two variables to hold the first name and the last name. These can be input by the user using input statements.

Get User Input

Prompt the user to enter their first name and assign this input to the first name variable. Then, ask the user to enter their last name and assign it to the last name variable.

Concatenate Names

Create a new variable that combines the first and last names. You can concatenate these strings using the '+' operator or a formatted string.

Display the Result

Output the concatenated result, which is the full name, to the user.

Key concepts

User Input Handling

In C++, handling user input is an essential skill that allows interaction with programs. To get data from the user, we typically use the `cin` object, along with the extraction operator (`>>`). This method reads input from the standard input stream, usually the keyboard.
It's important to ensure that the program prompts the user clearly. For example, if you want to get a first name and a last name, you might use two separate `cin` statements. This ensures that each piece of data is entered and stored correctly.
To improve the user experience, print messages to guide them through the input process, such as `Please enter your first name:`. This makes it clear what kind of input is expected.

• Use `std::cin` to read input.
• Clear prompts improve usability.
• Consider edge cases (e.g., spaces in names).

Be aware of input type mismatches and erroneous input, which can cause bugs if not handled properly. You may also want to use `getline(cin, stringVar)` if you expect spaces within the input.

String Concatenation

String concatenation is the process of joining two or more strings together into a single string. In C++, there are several ways to achieve this, but the most straightforward way is using the `+` operator.
This operator can be used to combine two `std::string` objects. For example, if you have a `firstName` and a `lastName`, the full name can be created by concatenating them: `fullName = firstName + " " + lastName;`.
The space character (" ") ensures that the first and last names are separated in the final output. Always remember to initialize strings before concatenation to avoid undefined behavior.

• Use the `+` operator for simple concatenation.
• Consider using `std::string::append` for appending operations.
• Ensure initialization to avoid runtime errors.

Additionally, C++ provides stringstreams or format strings for more complex concatenation tasks, which can handle various data types, not just strings.

Variable Declaration and Initialization

In C++, before you start using a variable, it must be declared and usually initialized. Declaring a variable means telling the compiler its data type and name. Initialization refers to setting it to a well-defined value.
For this task, you would declare two string variables to store the first name and last name. This is done using the `std::string` type in C++. For example, `std::string firstName;` and `std::string lastName;` are both declarations, and you can initialize these variables immediately with an initial value, if known.

• Declaring variables defines their type and scope.
• Initialization assigns an initial value.
• Proper initialization helps prevent errors.

Good practice involves always initializing your variables. This avoids unpredictable behavior since un-initialized variables can hold any value depending on what was left in memory.