cout << "Hello World!";
This line is a C++ statement. A statement is a simple or compound expression that can actually produce
some effect. In fact, this statement performs the only action that generates a visible effect in our first
program.
cout represents the standard output stream in C++, and the meaning of the entire statement is to insert
a sequence of characters (in this case the Hello World sequence of characters) into the standard output
stream (which usually is the screen).
cout is declared in the iostream standard file within the std namespace, so that's why we needed to
include that specific file and to declare that we were going to use this specific namespace earlier in our
code.
Notice that the statement ends with a semicolon character (;). This character is used to mark the end of
the statement and in fact it must be included at the end of all expression statements in all C++ programs
(one of the most common syntax errors is indeed to forget to include some semicolon after a statement).
return 0;
The return statement causes the main function to finish. return may be followed by a return code (in our
example is followed by the return code 0). A return code of 0 for the main function is generally interpreted
as the program worked as expected without any errors during its execution. This is the most usual way to
end a C++ console program.
You may have noticed that not all the lines of this program perform actions when the code is executed. There were lines containing only comments (those beginning by //). There were lines with directives for the compiler's preprocessor (those beginning by #). Then there were lines that began the declaration of a function (in this case,the main function) and, finally lines with statements (like the insertion into cout), which were all included within the block delimited by the braces ({}) of the main function.
The program has been structured in different lines in order to be more readable, but in C++, we do not have strict rules on how to separate instructions in different lines. For example, instead of
int main ()
{
cout << " Hello World!";
return 0;
}
We could have written:
int main () { cout << "Hello World!"; return 0; }
All in just one line and this would have had exactly the same meaning as the previous code.
In C++, the separation between statements is specified with an ending semicolon (;) at the end of each one, so the separation in different code lines does not matter at all for this purpose. We can write many statements per line or write a single statement that takes many code lines. The division of code in different lines serves only to make it more legible and schematic for the humans that may read it.
This line is a C++ statement. A statement is a simple or compound expression that can actually produce
some effect. In fact, this statement performs the only action that generates a visible effect in our first
program.
cout represents the standard output stream in C++, and the meaning of the entire statement is to insert
a sequence of characters (in this case the Hello World sequence of characters) into the standard output
stream (which usually is the screen).
cout is declared in the iostream standard file within the std namespace, so that's why we needed to
include that specific file and to declare that we were going to use this specific namespace earlier in our
code.
Notice that the statement ends with a semicolon character (;). This character is used to mark the end of
the statement and in fact it must be included at the end of all expression statements in all C++ programs
(one of the most common syntax errors is indeed to forget to include some semicolon after a statement).
return 0;
The return statement causes the main function to finish. return may be followed by a return code (in our
example is followed by the return code 0). A return code of 0 for the main function is generally interpreted
as the program worked as expected without any errors during its execution. This is the most usual way to
end a C++ console program.
You may have noticed that not all the lines of this program perform actions when the code is executed. There were lines containing only comments (those beginning by //). There were lines with directives for the compiler's preprocessor (those beginning by #). Then there were lines that began the declaration of a function (in this case,the main function) and, finally lines with statements (like the insertion into cout), which were all included within the block delimited by the braces ({}) of the main function.
The program has been structured in different lines in order to be more readable, but in C++, we do not have strict rules on how to separate instructions in different lines. For example, instead of
int main ()
{
cout << " Hello World!";
return 0;
}
We could have written:
int main () { cout << "Hello World!"; return 0; }
All in just one line and this would have had exactly the same meaning as the previous code.
In C++, the separation between statements is specified with an ending semicolon (;) at the end of each one, so the separation in different code lines does not matter at all for this purpose. We can write many statements per line or write a single statement that takes many code lines. The division of code in different lines serves only to make it more legible and schematic for the humans that may read it.
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