Statements and the structure of a program

• Computer program
  • A sequence of instructions.
• Statements
  • A type of instruction that causes the computer program to perform some action
  • Most (but not all statements) end with ;
  • Most common type of instruction in C++ programs, since they are the smallest independent unit of computation in C++
  • There are many different kinds of statements in C++:
    • Declaration statements
    • Jump statements
    • Expression statements
    • Compound statements
    • Selection statements (conditionals)
    • Iteration statements (loops)
    • Try blocks
• Function
  • A collection of statements that get executed sequentially (in order, from top to bottom).
  • Every C++ program must have a special function named main()
  • In programming, the name of a function (or object, type, template, etc…) is called its identifier
• Syntax error
  • A compiler error that occurs at compile-time when your program violates the grammar rules of the C++ language

Hello World

//main.cpp
#include <iostream> //preprocessor directive
 
int main()
{
	std::cout << "Hello world!";
	# return 0; 
	# if you don't return anything it assumes you're returning 0 anyway
}

• Preprocessor directive
  • #include preprocessor directive indicates that we would like to use the contents of the iostream library, which is part of the C++ standard library that allows us to read/write text from/to the console
  • #include <iostream>
    • Gets evaluated before we compile the file
    • includes all contents of the iostream file and paste into our file main.cpp