lec03_basic elements c++
TRANSCRIPT
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BASIC ELEMENTSOF
C++
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OBJECTIVES
To be able to use C++
input/outputand formatting
To become familiar with the
C++standard
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Outcome
Know how to write your firstprogram in C++ using basicelements of C++.
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Hello C++!
// This is a C++ program. It prints the sentence:// Welcome to C++ Programming.
#include using namespace std;
int main(){
cout
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Your First Program Explained
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Your First Program Explained
#include- read the file iostreamthat contains the definition for the stream
input/output package.
using namespace std;- all names in theprogram belong to the "standard namespace"
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cout
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New Line \n or endl
#include using namespace std;
int main(){
cout
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Comments
Comments can be written in two styles: Single line:
double can_volume = 0.355; // Liters in a 12-ouncecan
Multiline for longer comments:
/*This program computes the volume (in liters)of a six-pack of soda cans.
*/
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Basic data types in C++Data type C++ keyword Range
Integer int -32768 to 32767
Long integer long -4294967296 to 4294967295
Short integer short -128 to 127
Unsigned integer unsigned 0 to 65535
Character char 0 to 255
Floating point float 6 digits of precision
Double floating point double 12 digits of precision
Example of declaration
float amount; //Declares amount as a floating-point variable
int number; //Declares number as an integer variable
char ch; //Declares ch as a character variable
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C++ operators
Several classes of operators
Arithmetic
Relational
Logical
Assignment
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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 5a + b 9
a * b 14
a / b 3
a % b 1
a-- 6
b++ 3
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Arithmetic Operators (Integer)
#include using namespace std;
int main(){
// Integers Expression
cout
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Arithmetic Operators (Float)
#include using namespace std;
int main(){
// Floating-point expression
cout
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Arithmetic Operators (Mix)
#include using namespace std;
int main()
{ // Mix expression
cout
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Relational operators
Six relational operators in C++
The results is either TRUE(1)or FALSE (0)
E.g.
if a = 7andb = 5, then a < byields 0and a != byields 1Operator Meaning
< Less than
Greater than
>= Greater than or equal
= = Equal
!= Not equal
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Logical Operators
&&(logicalAND) Returns trueif both conditions are true
||(logical OR)
Returns trueif either of its conditions are true
!(logicalNOT, logical negation) Reverses the truth/falsity of its condition
Returns truewhen its condition is false
Logical operators used as conditions in loops
Expression Resulttrue && false falsetrue || false true!false true
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Assignment Operators
Most commonly used assignment operator is =(e.g. int Q = 5; )
Assignment expression abbreviations
c = c + 3;can be abbreviated as c += 3;using the additionassignment 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)
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Increment and Decrement Operators
Find the value of i and j (Assume i = 1)
int j = ++i // j is 2 , i is 2
int j = i++ // j is 1, I is 2
int j = --i // j is 0, I is 0
int j = i-- //j is 1, I is 0
T C i (C ti )
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Type Conversion (Casting)#include using namespace std;
int main(){
cout
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Allocating Memory with Constants
const doubleCONVERSION = 2.54;
const intNO_OF_STUDENTS = 20;
const charBLANK = ;
const doublePAY_RATE = 15.75;
Constant?A memory location whose content is not
allowed to change during program execution.
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Allocating Memory with Variables
doublesale; intnum1, num2;
charfirst;
stringstr;
Variable?A memory location whose content maychange during program execution.
num1 = 4; num2 = 4*5-11;
sale = 0.02 * 1000;
first = D; str = It is a sunny day.;
i l d i
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#include using namespace std;
int main(){
const intNO_STUD = 20;
stringstr;str = All are good students;
cout
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Input (Read) Statement#include using namespace std;
int main()
{int feet, inches;
cout feet >> inches;cout
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Increment & Decrement Operators#include using namespace std;
int main()
{int num = 0, num2 = 0, tot = 5;
num++;
num2 = num2 + 1;cout
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Preprocessor Directives
#include #include using namespace std;
int main(){
int num;string name;
coutnum;
coutname;
return 0; }
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Lets Try!
Write a program that prompts the user to enter twotest scores and then prints the average test score.(Assume test scores are decimal numbers.)
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Lets Try!
Write a program that converts Fahrenheit degrees toCelsius using the formula :
Celcius = 5/9 * (Fahrenheit 32)