C++ Programming Code Examples
C++ > Beginners Lab Assignments Code Examples
main() Function of C++
/* main() Function of C++
The main() function is called when the program starts after initialization of the non-local objects with static storage duration. It is the primary entry point of any C++ program that is executed in a hosted environment. In C++, the main() function is written after the class definition. The main function of C++ has several special properties. These are:
main() function cannot be used anywhere within the program
In particular, cannot be called recursively
Its address cannot be taken for reuse
main() function cannot be predefined and cannot be overloaded.
main() function cannot be declared as static, inline or constexpr
The return type of the main() function cannot be deduced (i.e. auto main() {... is not allowed in C++).
The main() function for both the function definition (discussed above) will be same. You have to create objects of the class inside the main() and using that object along with the dot (.) operator member functions will be called. */
int main()
{
Sq S1;
S1.a = 6;
S1.square();
cout << " Square of the number is :"<< S1.square();
}
Inline function is one of the important feature of C++. So, let's first understand why inline functions are used and what is the purpose of inline function? When the program executes the function call instruction the CPU stores the memory address of the instruction following the function call, copies the arguments of the function on the stack and finally transfers control to the specified function. The CPU then executes the function code, stores the function return value in a predefined memory location/register and returns control to the calling function. This can become overhead if the execution time of function is less than the switching time from the caller function to called function (callee). For functions that are large and/or perform complex tasks, the overhead of the function call is usually insignificant compared to the amount of time the function takes to run. However, for small, commonly-used functions, the time needed to make the function call is often a lot more than the time needed to actually
n C++, we can change the way operators work for user-defined types like objects and structures. This is known as operator overloading. Suppose we have created three objects c1, c2 and result from a class named Complex that represents complex numbers. Since operator overloading allows us to change how operators work, we can redefine how the + operator works and use it to add the complex numbers of c1 and c2 by writing the following code:
The function in C++ language is also known as procedure or subroutine in other programming languages. To perform any task, we can create function. A function can be called many times. It provides modularity and code reusability. Functions are used to provide modularity to a program. Creating an application using function makes it easier to understand, edit, check... Function declaration, is done to tell the compiler about the existence of the function. Function's return type, its name & parameter list is mentioned. Function body is written in its definition. Functions are called by their names. If the function is without argument, it can be called directly using its name. But for functions with arguments, we have two ways to call them:
The C++ comments are statements that are not executed by the compiler. The comments in C++ programming can be used to provide explanation of the code, variable, method or class. If we write comments on our code, it will be easier for us to understand the code in the future. Also, it will be easier for your fellow developers to understand the code. By the help of comments, you can hide the program code also. There are two types of comments in C++: • Single Line comment. • Multi Line comment
A program shall contain a global function named main, which is the designated start of the program in hosted environment. main() function is the entry point of any C++ program. It is the point at which execution of program is started. When a C++ program is executed, the execution control goes directly to the main() function. Every C++ program have a main() function.
The cout is a predefined object of ostream class. It is connected with the standard output device, which is usually a display screen. The cout is used in conjunction with stream insertion operator (<<) to display the output on a console. On most program environments, the standard output by default is the screen, and the C++ stream object defined to access it is cout. The "c" in cout refers to "character" and "out" means "output". Hence cout means "character output". The cout object is used along with the insertion operator << in order to display a stream of characters.
To "delete element" from an array in C++, you have to first ask to the user to enter the array size then ask to enter the array element, ask to enter the element which is "to be deleted".
Program takes a Positive integer & Calculates the factorial of the number. First user enter 6 then, Factorial will be equal to '1*2*3*4*5*6' 720. Learn to Find the "Factorial" of a number
