Q.Write the names of the correct header files, which must be included in the following C++ code to compile the code successfully: void main() { char L[]="CS 2018"; int N=strlen(L); cout<<L[N-1]; }

The key idea is to identify the standard library components used in the code and include their corresponding header files.

1. The strlen() function, which calculates the length of a C-style string, is declared in the <cstring> header.
2. The cout object, used for standard output, is part of the C++ iostream library and is declared in the <iostream> header. …

When writing C++ programs, we often use functions and objects that are not defined directly within our code but are part of the C++ Standard Library. For the compiler to understand how to use these pre-defined components, it needs to know their declarations – essentially, their "blueprints." These blueprints are stored in special files called header files. By including the appropriate header files, we make these declarations available to our program, allowing the compiler to link our code with the library's implementations.

Let's break down the given code snippet to identify which standard library components are used and, consequently, which header files are required.

1. Analyze the strlen function:

   The line int N=strlen(L); uses the strlen function. This function is a standard C-style string manipulation function that calculates the length of a null-terminated character array (string). In C++, functions related to C-style strings are typically declared in the <cstring> header file.

   Note

   In C, the equivalent header is <string.h>. While <string.h> can often be used in C++ for backward compatibility, the C++ standard library provides <cstring> which places these functions within the std namespace (though strlen is often also available in the global namespace for convenience). For modern C++ code, <cstring> is the preferred choice.

2. Analyze the cout object:

   The line cout<<L[N-1]; uses cout. This is the standard output stream object in C++, used for printing data to the console. The cout object, along with other input/output functionalities like cin and cerr, is part of the iostream library. Its declaration is found in the <iostream> header file. …