c++ syntax

c++_syntax.md

C++ syntax

• cppreference.com
• strongly statically typed
• not a pure OOP, more hybrid

example:

// preprocessor directive
// contains all the definitions you need for text input / output streams
#include <iostream>
// tells the program you are using a name grouping
// dont then have to do std::cout
using namespace std;

// comments go up here, purpose, header

int main() {
	// program bodyz

	// for now, return 0
	// exit code 0 means no errors specifically in the main function
	return 0;
}

• main is a reserved function name, is run first

#include <iostream>
using namespace std;

int main() {
	float inches, mm;
	cout << "A string sentence that will print to console"
	cout << "More string sentence" << endl;

	cin >> inches;

	cout << "More output here" << inches << "more even"
}

- `<<` means insertion operator, pushes contents into the `cout	` stream
- `endl` new line
- `>>` extraction operator, accepts input from the console

variables

• generally declared at the top of the function
  • avoid defining local variables within blocks

// can declare line by line
float feet;
// or same typed together
float inches, mm;

- these are uninitialized, and can be very dangerous. Complier can do whatever it wants. Try to always assign values at time of variable creation.
- type is declared

• must start with a letter, cannot use $
• primitive data types: float, double, int, short, long, char, bool
  • float is small, double is bigger
• string is not listed as it is user defined data type and not built into the language
  • this class will use arrays of characters to represent strings
• avoid global variables (defined outside of a function)
  • constant globals are fine
  • all caps const int A_VERY_CONSTANT = 42

stream stuff

• cin >> inches
  • will skip leading whitespaces
  • if the wrong datatype is in the input buffer, silent error
    • sometimes will need to use cin.clear() to clear the error state
    • will stay at the same place for the mismatched variable, even though content was entered, in the iostream
• \n newline character
  • \ escape character
  • can behave similarly to endl in linux environments
• cin.ignore(number, '\n')
  • cin.ignore(number) do not use, unsafe
• cin.get()
  • reads a single character, takes out of the stream
• cin.peek()
  • looks into the stream without removing it
    • does not modify buffer

io formatting

• precision matters
  • default, no more than 6 digits
• cout.precision(3)
  • sets the precision for cout until changed otherwise
• cout << setprecision(3)
  • only sets the precision for the cout in the stream currently used for
• cout.setf(ios::showpoint)
  • set format can be passed a number of formatting specifications