C++ Programming Code Examples
C++ > Beginners Lab Assignments Code Examples
Multiline Comments in C++ programming language
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/* Multiline Comments in C++ programming language
If you want to write a multiline comment you have to write "/*" at the start of the comment. After this you can write as many number of lines of description. When you are done with writing multiline comment then you have to close multiline comment. It is done by the "*/" symbol. */
/*start line
This is a multiline comment
Anything between start (/ *) and end (* /)
will be ignored by the compiler
end line */
//include a header file from Standard Library
#include <iostream>
using namespace std;
//the work of the program starts from function called main
int main()
{
//use standard (console) to output message "Hello World"
cout << "Hello world" << endl;
//wait for user to press a key
cin.ignore();
//return a value to the system when program finish its execution successfully
return 0;
}
A return statement ends the processing of the current function and returns control to the caller of the function. A value-returning function should include a return statement, containing an expression. If an expression is not given on a return statement in a function declared with a non-void return type, the compiler issues an error message. If the data type of the expression is different from the function return type, conversion of the return value takes place as if the value of the expression were assigned to an object with the same function return type.
Consider a situation, when we have two persons with the same name, jhon, in the same class. Whenever we need to differentiate them definitely we would have to use some additional information along with their name, like either the area, if they live in different area or their mother's or father's name, etc. Same situation can arise in your C++ applications. For example, you might be writing some code that has a function called xyz() and there is another library available which is also having same function xyz(). Now the compiler has no way of knowing which version of xyz() function you are referring to within your code.
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.
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.
Extract and discard characters. Extracts characters from the input sequence and discards them, until either n characters have been extracted, or one compares equal to delim. The function also stops extracting characters if the end-of-file is reached. If this is reached prematurely (before either extracting n characters or finding delim), the function sets the eofbit flag. Internally, the function accesses the input sequence by first constructing a sentry object (with noskipws set to true). Then (if good), it extracts characters from its associated stream buffer object as if calling its member functions sbumpc or sgetc, and finally destroys the sentry object before returning. Function returns the istream object (*this).
#include is a way of including a standard or user-defined file in the program and is mostly written at the beginning of any C/C++ program. This directive is read by the preprocessor and orders it to insert the content of a user-defined or system header file into the following program. These files are mainly imported from an outside source into the current program. The process of importing such files that might be system-defined or user-defined is known as File Inclusion. This type of preprocessor directive tells the compiler to include a file in the source code program.
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
In this program, "enter the size "of 2 matrix at first. To multiply two matrices, the number of columns of first matrix should be equal to the "number of rows" to second matrix. C++ Code
