Question

\((\text { Length of a String })\) Write a program that inputs a string from the keyboard and determines the length of the string. Print the string in a field width that is twice the length of the string.

Short answer

To display the length of a user-input string and print it with a field width twice its length, input the string, calculate its length, double the length to find the field width, and then print the string accordingly.

Step-by-step solution

Input the String

Prompt the user to input a string from the keyboard. Store this input in a variable for later use.

Determine String Length

Use the appropriate function or method provided by the programming language to determine the length of the string that the user has entered. Store the length in a variable.

Calculate Field Width

Calculate the field width, which is twice the length of the string. Store it in another variable.

Print the String

Print the string using the calculated field width. Ensure that the printed output has a field width that is exactly twice the length of the input string.

Key concepts

C++ programming

C++ programming is a versatile endeavor that evolves around writing code in the C++ language, a widely-used mid-level programming language that combines both high and low-level language features. To excel in C++, one needs to understand the basics, such as data types, variables, control structures (such as loops and conditionals), functions, and more complex topics like object-oriented programming and memory management.

As an integral part of learning C++, string handling becomes an essential skill due to its common usage in coding tasks. Student exercises often involve simple programs to manipulate text, encouraging a firm understanding of how strings are used and managed within C++ applications.

String handling in C++

String handling in C++ is facilitated by the use of the std::string class included in the standard library. The class provides a ton of functionality for dealing with sequences of characters. It encompasses capabilities such as accessing individual characters, modifying strings, concatenating, and comparing strings. It is crucial to understand that unlike simple character arrays, the std::string class allows dynamic resizing and provides several member functions to make string operations more intuitive.

For instance, you can determine the length of a string by using the length() or size() member functions which return the number of characters in the string. In addition, C++ also supports C-style string handling with functions like strlen(), but these are less safe and offer less functionality compared to std::string.

Determining string length

Determining the length of a string in C++ is straightforward thanks to the length() or size() functions provided by the std::string class. When you need to use the length of a string to perform other operations, such as formatting output or substrings, retrieving this information is as simple as calling one of these functions.

In an educational setting, this concept often relates to exercises that demonstrate how to operate on strings based on their size, which is a key skill in developing more complex programs. By seamlessly integrating string length determination into your programs, you enable dynamic handling of textual data - a fundamental concept in modern software development.

Input/output in C++

Input/output in C++ is typically handled using the standard streams - cin for input and cout for output, part of the iostream library. For beginners, grasping these two streams is essential as they allow for interaction with the user.

When a program needs user input, cin is used in conjunction with the extraction operator (>>). Output is handled by cout along with the insertion operator (<<), which allows for data to be printed to the console. Moreover, formatting options are available to control how the data is presented, such as setting field widths, which is a valuable tool when outputting structured data, like tabular information or ensuring visually consistent layouts.