C++ Part 28

Strings

A char literal is indicated with single quotes (e.g., ’c’), while a string literal is indicated with double quotes (e.g., “abc”).
These are C++ strings and are in library:

• =: Assignment
• <,> , <=, >= ,== , ! =, . . .:
• s[i]: Indexing, i.e., i’th character of s (i ≥ 0)
•  Ex: string s = ‘‘cat’’; char c = s[2] sets c to ’t’
•  + :  Concatenation (overloaded for characters)
• Ex: ‘‘apple’’ + ‘‘pear’’ evaluates to “applepear” while ‘‘apple’’+’s’ evaluates to “apples”
• s.empty(): true if s is an empty string 
• s.length(): length of s (≥ 0) 

//Assignment and comparison operators work for strings but NOT
for all C++ data types.

<<, >> : input/output (still uses whitespace as delimiter).
e.g., cin >> s1 >> s2 would assign “Navid” to s1 and “Plus” to s2,
if the user typed “Navid Plus”.

C++ Part 26

Void Functions

A void function performs some action, but does not return a value. For a void function, a function
invocation (function call) is a statement that can be used like any other C++ statement.

Example :

// void function example by NavidPlus.BlogSpot.com #include <iostream> using namespace std; void printmessage () {  cout << "This message is created by NavidPlus!"; } int main () {  printmessage (); }

Intro to C++ Part 6

A Sample C++ Program  

##include <iostream>
using namespace std;The following line says that main is a function with no parameters that returns an int(integer) value:int main( )Some compilers will allow you to omit the int or replace it with void, which indicates
a function that does not return a value. However, the previous form is the most
universally accepted way to start the main function of a C++ program.
The program ends when the following statement is executed:return 0;