Post on 27-Oct-2014
C++ Programming
Revision
Hello World!
Basic fundamental data types
C++ operators
• Several classes of operators– Arithmetic– Relational – Logical – Assignment
Arithmetic operators• Seven arithmetic operators in C++ ( E.g. int a = 7, b = 2; )
Operators Action
- Substraction
+ Addition
* Multiplication
/ Division
% Modulus division
- - Decrement
+ + Increment
Expression Value
a - b 5
a + b 9
a * b 14
a / b 3
a % b 1
a-- 6
b++ 3
Arithmetic Operators#include <iostream>using namespace std;
int main(){ // Integers Expression
cout << "2 + 5 = "<< 2 + 5 << endl; cout << "4 * 3= "<< 4 * 3 << endl; // Floating-point expression cout<<"4.0 * 3.0= "<<4.0 * 3.0<<endl; cout<<"5.0 / 2.0= "<<5.0 / 2.0<<endl;
return 0;}
Relational operators• Six relational operators in C++• The results is either TRUE (1) or FALSE (0)• E.g. if a = 7 and b = 5, then a < b yields 0 and a != b yields 1
Operator Meaning
< Less than
<= Less than or equal
> Greater than
>= Greater than or equal
= = Equal
!= Not equal
Logical Operators• && (logical AND)– Returns true if both conditions are true
• || (logical OR)– Returns true if either of its conditions are true
• ! (logical NOT, logical negation)– Reverses the truth/falsity of its condition– Returns true when its condition is false
• Logical operators used as conditions in loops Expression Resulttrue && false falsetrue || false true!false true
Assignment Operators
• Most commonly used assignment operator is = (e.g. int Q = 5; )
• Assignment expression abbreviationsc = c + 3; can be abbreviated as c += 3; using the
addition assignment operator
• Examples of other assignment operators include:d -= 4 (d = d - 4)e *= 5 (e = e * 5)f /= 3 (f = f / 3)g %= 9 (g = g % 9)
Memory Variables• double sale;• int num1, num2;• char first;• string str;
• Variable? A memory location whose content may change during program execution.
• num1 = 4; num2 = 4*5-11;• sale = 0.02 * 1000;• first = ‘D’; str = “It is a sunny day.”;
Constants Variables
• const double CONVERSION = 2.54;• const int NO_OF_STUDENTS = 20;• const char BLANK = ‘ ‘;• const double PAY_RATE = 15.75;
• Constant? A memory location whose content is not allowed to change during program execution.
#include <iostream>using namespace std;
int main(){
const int NO_STUD = 20;
string str; str = “All are good students”;
cout<<“Num of students is “<<NO_STUD; cout<<str; str = “Some are so-so”; cout<<str;
return 0; }
Input (Read) Statement
int main(){ int feet, inches;
cout<<“Enter two integers separated by spaces: “; cin>> feet >> inches; cout<<endl;
cout<< “Feet = “<< feet << endl; cout<< “Inches = “<< inches << endl; system(“pause"); return 0;}
Increment & Decrement Operators
int main(){ int num = 0, num2 = 0, tot = 5;
num++; num2 = num2 + 1; cout<< num <<“ “<< ++num <<endl;
tot--; cout<< tot; system("Pause"); return 0;}
Lets Try!
• Write a program that prompts the user to enter five test scores and then prints the average test score. (Assume test scores are decimal numbers.)