Before diving into the details about the use of `inline` function in C++, it is necessary to understand the concept of functions in general in the realm of C++. A function is a block of code that performs a specific task and is basically designed for code reusability. C++, being an extension of C language has all features of C and plus an addition of new features like classes, objects and functions. Among these, the concept of `inline` function stands out when it comes to optimizing the execution of a program.
With this understanding in mind, the essential role of `inline` function is to mitigate the cost of calls to small functions. It’s worth mentioning that when a function gets called, a certain amount of overhead is involved. This overhead includes the storing of crucial information and the control transferred to the function that has been called. But, with an `inline` function, the compiler simply replaces the function call with the corresponding function code, thus eliminating the overhead of function call. This comes with a benefit of improved speed or performance of the code, especially for small functions.
#include
using namespace std;
inline void display(){
cout << "Inline Function in C++" << endl;
}
int main(){
display();
return 0;
}
[/code]
The above example presents a simple `inline` function in C++. The `inline` keyword notifies the compiler to insert a copy of the function body each place that the function is called.
The Concept of Inline Function
The term `inline` suggests placing in line. An `inline` function’s definition is placed at the point where the function is called, just like macro expansion in C++. This signifies that the overhead included during a function call is nullified because there is no need to jump to another location and then return, as the function body gets placed into the calling function.
When to use Inline Function?
An `inline` function is certainly a powerful tool, but it should be used judiciously. Its main purpose is to increase execution speed by avoiding overhead of function calls which is generally beneficial for small functions. For larger functions, the increase in code complexity and potential increase in program size might outweigh the benefits. It’s also crucial to remember that declaring a function as `inline` does not necessarily mean compiler will agree to it. The ultimate decision is up to the compiler.
Dissecting The Inline Function Code
Coming back to the example provided, let’s dissect each section of the C++ code involving `inline` function.
[code lang=”C++”]
#include
using namespace std;
The first two lines of the code informs the compiler about the libraries to use.
inline void display(){
cout << "Inline Function in C++" << endl;
}
[/code]
This part of code is where the `inline` function has been defined. Here, `void` refers to the return type of function which is nothing, followed by the function name `display()`. Inside it, a message is being printed.
[code lang="C++"]
int main(){
display();
return 0;
}
[/code]
In the `main()` function, the function `display()` is being called. As it is an `inline` function, the compiler would replace this function call - `display()` with inline function definition.
This provides an overall glance at the concept and utilization of `inline` functions within C++ along with a basic implementation example.
Libraries and Functions in C++
In the above example, we used the `
When it comes to functions, there are two major types in C++: built-in functions and user-defined functions. Built-in functions, also known as library functions are pre-defined and come along with the compiler. User-defined functions, as the name suggests, are defined by the user during the program.
In conclusion, an `inline` function is an optimization technique used primarily to increase program execution efficiency by eliminating the overhead produced during a function call. Understanding when to use `inline` functions can be an important tool to a C++ programmer and can be utilized to make code run faster and more efficiently.