Difference between revisions of "Hello World"

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Line 4: Line 4:
 
int main()
 
int main()
 
{
 
{
   std::cout << "Hello World!";
+
   std::cout << "Hello World!" << std::endl;
 +
  return 0; // Must return an integer (int main)
 
}
 
}
 
</syntaxhighlight>
 
</syntaxhighlight>
Line 1: #include <iostream><br/>
+
'''Line 1: #include <iostream><br/>'''
 
Lines beginning with a hash sign (#) are directives read and interpreted by what is known as the preprocessor. They are special lines interpreted before the compilation of the program itself begins. In this case, the directive #include <iostream>, instructs the preprocessor to include a section of standard C++ code, known as header iostream, that allows to perform standard input and output operations, such as writing the output of this program (Hello World) to the screen.
 
Lines beginning with a hash sign (#) are directives read and interpreted by what is known as the preprocessor. They are special lines interpreted before the compilation of the program itself begins. In this case, the directive #include <iostream>, instructs the preprocessor to include a section of standard C++ code, known as header iostream, that allows to perform standard input and output operations, such as writing the output of this program (Hello World) to the screen.
  
Line 5: std::count << "Hello World!";<br/>
+
'''Line 5: std::cout << "Hello World!" << std::endl;<br/>'''
 
This statement has three parts: First, std::cout, which identifies the Standard Character output Device (usually, this is the computer screen). Second, the insertion operator (<<), which indicates that what follows is inserted into std::cout. Finally, a sentence within quotes ("Hello world!"), is the content inserted into the standard output.
 
This statement has three parts: First, std::cout, which identifies the Standard Character output Device (usually, this is the computer screen). Second, the insertion operator (<<), which indicates that what follows is inserted into std::cout. Finally, a sentence within quotes ("Hello world!"), is the content inserted into the standard output.
  
Note one doesn't have to use the :: (namespace) operator. if need be one can set a using directive for the namespace so everything contained within it is moved directly to the local namespace.
+
Note one doesn't have to use the :: (namespace) operator, if need be one can set a using directive for the namespace so everything contained within the namespace is accessible directly from the scope of the file.
  
 
<syntaxhighlight lang="cpp" line>
 
<syntaxhighlight lang="cpp" line>
Line 21: Line 22:
 
int main()
 
int main()
 
{
 
{
   cout << "Hello World!";
+
   cout << "Hello World!" << std::endl;
 +
  return 0; // Must return an integer (int main)
 
}
 
}
 
</syntaxhighlight>
 
</syntaxhighlight>
  
in this case std::cout is no longer required &amp one can just use cout.
+
in this case std::cout is no longer required & one can just use the keyword cout.

Revision as of 08:38, 12 September 2017

1 #include <iostream>
2 
3 int main()
4 {
5   std::cout << "Hello World!" << std::endl;
6   return 0; // Must return an integer (int main)
7 }

Line 1: #include <iostream>
Lines beginning with a hash sign (#) are directives read and interpreted by what is known as the preprocessor. They are special lines interpreted before the compilation of the program itself begins. In this case, the directive #include <iostream>, instructs the preprocessor to include a section of standard C++ code, known as header iostream, that allows to perform standard input and output operations, such as writing the output of this program (Hello World) to the screen.

Line 5: std::cout << "Hello World!" << std::endl;
This statement has three parts: First, std::cout, which identifies the Standard Character output Device (usually, this is the computer screen). Second, the insertion operator (<<), which indicates that what follows is inserted into std::cout. Finally, a sentence within quotes ("Hello world!"), is the content inserted into the standard output.

Note one doesn't have to use the :: (namespace) operator, if need be one can set a using directive for the namespace so everything contained within the namespace is accessible directly from the scope of the file.

1 #include <iostream>
2 using namespace std;
3 
4 int main()
5 {
6   cout << "Hello World!" << std::endl;
7   return 0; // Must return an integer (int main)
8 }

in this case std::cout is no longer required & one can just use the keyword cout.