C++ Examples
Dave Braunschweig
Overview
The following examples demonstrate data types, arithmetic operations, and input in C++.
Data Types
// This program demonstrates variables, literal constants, and data types. #include <iostream> #include <sstream> using namespace std; int main() { int i; double d; string s; bool b; i =<PHONE_NUMBER>; d = 1.23456789012345; s = "string"; b = true; cout << "Integer i = " << i << endl; cout << "Double d = " << d << endl; cout << "String s = " << s << endl; cout << "Boolean b = " << b << endl; return 0; }
Output
Integer i =<PHONE_NUMBER> Real r = 1.23457 String s = string Boolean b = 1
Discussion
Each code element represents:
//
begins a comment#include <iostream>
includes standard input and output streams#include <sstream>
includes standard string streamsusing namespace std
allows reference tostring
,cout
, andendl
without writingstd::string
,std::cout
, andstd::endl
.int main()
begins the main function, which returns an integer value{
begins a block of codeint i
defines an integer variable named i;
ends each line of C++ codedouble d
defines a double floating-point variable named dstring s
defines a string variable named sbool b
defines a Boolean variable named bi = , d = , s =, b =
assign literal values to the corresponding variablescout
is standard output<<
directs the next element to standard outputendl
ends the current linereturn 0
returns the value 0 from main, indicating the main function completed successfully}
ends a block of code
Arithmetic
// This program demonstrates arithmetic operations. #include <iostream> #include <sstream> using namespace std; int main() { int a; int b; a = 3; b = 2; cout << "a = " << a << endl; cout << "b = " << b << endl; cout << "a + b = " << a + b << endl; cout << "a - b = " << a - b << endl; cout << "a * b = " << a * b << endl; cout << "a / b = " << a / b << endl; cout << "a % b = " << a + b << endl; return 0; }
Output
a = 3 b = 2 a + b = 5 a - b = 1 a * b = 6 a / b = 1 a % b = 5
Discussion
Each new code element represents:
+, -, *, /, and %
represent addition, subtraction, multiplication, division, and modulus, respectively.
Temperature
// This program converts an input Fahrenheit temperature to Celsius. // // References: // https://www.mathsisfun.com/temperature-conversion.html // https://en.wikibooks.org/wiki/C%2B%2B_Programming #include <iostream> using namespace std; int main() { double fahrenheit; double celsius; cout << "Enter Fahrenheit temperature:" << endl; cin >> fahrenheit; celsius = (fahrenheit - 32) * 5 / 9; cout << fahrenheit << "° Fahrenheit is " << celsius << "° Celsius" << endl; return 0; }
Output
Enter Fahrenheit temperature: 100 100° Fahrenheit is 37.7778° Celsius
Discussion
Each new code element represents:
cin >> fahrenheit
reads the next integer from standard input and assigns the value to the fahrenheit variable