c++ chapter 2
TRANSCRIPT
UNIT -2DATA TYPES ,
VARIABLES AND OPERATORS
OverviewObjectivesC++ data types, constant and variableC++ keywordsInput Output : cin, coutHands On!
DATA TYPE A data type determines the type of the
data that will be stored, usually, in the computer memory (RAM).
Type statements in C++ are used to allow the compiler to: reserve blocks of memory to store information give the reserved blocks of memory a symbolic
name so that the data contained in this block of memory can be manipulated by referring to this name in future C++ statements.
Data TypesC++ provides three fundamental data types:
- int (integers ) ex: 1 , -8 ,0 ,etc - float (decimal numbers) ex: 2.03 , -7.15 ,
0.0 , etc - char (character) ex: ‘a’ , ‘A’ , ‘1’, etc
0 is not float 0.0 is float
Name Description Size* Range*char Character 1byte signed: -128 to 127
unsigned: 0 to 255short int(short) Short Integer. 2bytes
signed: -32768 to 32767unsigned: 0 to 65535
int Integer. 2 or 4 bytes
signed: -2147483648 to 2147483647unsigned: 0 to 4294967295
long int(long) Long integer. 4bytes
signed: -2147483648 to 2147483647unsigned: 0 to 4294967295
boolBoolean value. It can take one of two values: true or false.
1byte true or false
float Floating point number. 4bytes +/- 3.4e +/- 38 (~7 digits)
double Double precision floating point number. 8bytes +/- 1.7e +/- 308 (~15
digits)long double Long double precision
floating point number. 8bytes +/- 1.7e +/- 308 (~15 digits)
Exercise What is the suitable data type for the following?
number of student in your class - unsigned int
your matrix elements - float
assignment marks for this subject - float
the distance to the moon (the distance to the moon is over 200,000 miles) - long double
last month's checking account balance - float /double
a counter used to count the number of lines in a text file - int
number of people living in Malaysia - long
the temperature used in a chemistry formula - float
Variables variable
a valid identifier whose value can change during the course of execution of a program
general form of the declarations: data-type variable_name;
example:int mass; double x, speed, dragForce;
Declaration of Variables when a variable is declared, you can initialize it in two alternative but equivalent ways
int mass = 22; or int mass; //(garbage value)mass = 22;
Declaration of string variableexample:
string name = “Mohamad”;
Variables// Declaration of variables
#include <iostream> using namespace std;
int main () { short x = 22, y = 11, z; z = x - y; cout << "z = " << z << endl; int p = 3; int q = x * y * z - 2 * p; cout << "q = " << q << endl; return 0; }
Exercise :Correct the following errors long Float x; long x; int code = three, int code = 3; const int array size; const int array_size;
Declare the following variable:Name Type Initial value
marks double Nonegrade char Aprice float 10.0num_1 int 5msg string Hello Worldresult bool true
Scope of Variablevariable can have either local or global scopescope (visibility) of local variables is limited to the block enclosed in braces ({ }) where they are declaredglobal variables are declared outside of all blocks and their scope are the entire program, i.e. the main body of the source code.
What is the Scope of A variable ?
Scope refers to the visibility of variables. In otherwords, which parts of your program can see or use it. Normally, every variable has a global scope. Once defined, every part of your program can access a variable.
A scope is a region of the program and broadly speaking there are three places, where variables can be
declared:
Inside a function or a block which is called local variables,In the definition of function parameters which is called formal parameters.Outside of all functions which is called global variables.
Operators in C++An operator is a symbol that tells the compiler to perform specific mathematical or logical manipulations. C++ is rich in built-in operators and provides the following types of operators:Arithmetic OperatorsRelational OperatorsLogical OperatorsBitwise OperatorsAssignment Operators
Arithmetic Operators:Assume variable A holds 10 and variable B holds 20
Operator
Description Result
+ Adds two operands 30
- Subtracts second operand from first -10
* Multiplies both Operands 200
/ Divides numerator by De-numerator B/A=2
% Modulus Operator and reminder of after integer division
A%B=0
++ Increment operator , increases integer value by one
11 A++
-- Decrement Operator, Decreases Integer Value by One
9
7/8/2014
By Himanshu Kaushik | ApplicationDeveloper.in |
Himanshukaushik.in
main(){
int a = 21; int b = 10; int c ; c = a + b; cout << "Line 1 - Value of c is :" << c << endl ; c = a - b; cout << "Line 2 - Value of c is :" << c << endl ; c = a * b; cout << "Line 3 - Value of c is :" << c << endl ;
c = a / b; cout << "Line 4 - Value of c is :" << c << endl ; c = a % b; cout << "Line 5 - Value of c is :" << c << endl ; c = a++; cout << "Line 6 - Value of c is :" << c << endl ; c = a--; cout << "Line 7 - Value of c is :" << c << endl ; return 0;
}
Relational OperatorsAssume variable A holds 10 and variable holds 20
Operator
Description Example
== Checks if the Value of two Operands are Equal or not , if yes then condition becomes True
(A==B) is not true
!= Checks if the value of two operands are equal or not , if values are not equal then condition becomes true
(A!=B) is true
> Checks if the value of Left operand is greater than the value of right operand , if yes then condition becomes true,
(A>B) is not true
< , >= , <= are relationals operators
Bitwise OperatorsBitwise operator works on bits and perform bit-by-bit operation.
P Q P & Q P|Q P^Q
0 0 0 0 0
0 1 0 1 1
1 1 1 1 0
1 0 0 1 1
if A = 60; and B = 13Assume if A = 60; and B = 13; now in binary format they will be as follows:
A = 0011 1100 B = 0000 1101 A&B = 0000 1100 A|B = 0011 1101 A^B = 0011 0001 ~A = 1100 0011
Operator
Description Result
& Binary AND Operator copies a bit to the result if it exists in both operands.
(A & B) will give 12 which is 0000 1100
| Binary OR Operator copies a bit if it exists in either operand.
(A | B) will give 61 which is 0011 1101
^ Binary XOR Operator copies the bit if it is set in one operand but not both.
(A ^ B) will give 49 which is 0011 0001
Operator
Description Result
~
Binary Ones Complement Operator is unary and has the effect of 'flipping' bits.
(~A ) will give -61 which is 1100 0011 in 2's complement form due to a signed binary number.
<< Binary Left Shift Operator. The left operands value is moved left by the number of bits specified by the right operand.
A << 2 will give 240 which is 1111 0000
>> Binary Right Shift Operator. The left operands value is moved right by the number of bits specified by the right operand.
A >> 2 will give 15 which is 0000 1111
By Himanshu Kaushik | ApplicationDeveloper.in |
Himanshukaushik.in
main(){ unsigned int a = 60; // 60 = 0011 1100 unsigned int b = 13; // 13 = 0000 1101 int c = 0;
c = a & b; // 12 = 0000 1100 cout << "Line 1 - Value of c is : " << c << endl ;
c = a | b; // 61 = 0011 1101 cout << "Line 2 - Value of c is: " << c << endl ;
c = a ^ b; // 49 = 0011 0001 cout << "Line 3 - Value of c is: " << c << endl ;
c = ~a; // -61 = 1100 0011 cout << "Line 4 - Value of c is: " << c << endl ;
c = a << 2; // 240 = 1111 0000 cout << "Line 5 - Value of c is: " << c << endl ;
c = a >> 2; // 15 = 0000 1111 cout << "Line 6 - Value of c is: " << c << endl ;
return 0;}
Assignment Operators
By Himanshu Kaushik | ApplicationDeveloper.in |
Himanshukaushik.in
Operator Description Example
= Simple assignment operator, Assigns values from right side operands to left side operand
C = A + B will assign value of A + B into C
+= Add AND assignment operator, It adds right operand to the left operand and assign the result to left operand
C += A is equivalent to C = C + A
-= Subtract AND assignment operator, It subtracts right operand from the left operand and assign the result to left operand
C -= A is equivalent to C = C - A
Assignment OperatorsOperator Description Example
*= Multiply AND assignment operator, It multiplies right operand with the left operand and assign the result to left operand
C *= A is equivalent to C = C * A
/= Divide AND assignment operator, It divides left operand with the right operand and assign the result to left operand
C /= A is equivalent to C = C / A
%= Modulus AND assignment operator, It takes modulus using two operands and assign the result to left operand
C %= A is equivalent to C = C % A
7/8/2014
By Himanshu Kaushik | ApplicationDeveloper.in |
Himanshukaushik.in
main(){ int a = 21; int c ;
c = a; cout << "Line 1 - = Operator, Value of c = : " <<c<< endl ;
c += a; cout << "Line 2 - += Operator, Value of c = : " <<c<< endl ;
c -= a; cout << "Line 3 - -= Operator, Value of c = : " <<c<< endl ;
c *= a; cout << "Line 4 - *= Operator, Value of c = : " <<c<< endl ;
c /= a; cout << "Line 5 - /= Operator, Value of c = : " <<c<< endl ;
c = 200; c %= a; cout << "Line 6 - %= Operator, Value of c = : " <<c<< endl ;
c <<= 2; cout << "Line 7 - <<= Operator, Value of c = : " <<c<< endl ;
c >>= 2; cout << "Line 8 - >>= Operator, Value of c = : " <<c<< endl ;
c &= 2; cout << "Line 9 - &= Operator, Value of c = : " <<c<< endl ;
c ^= 2; cout << "Line 10 - ^= Operator, Value of c = : " <<c<< endl ;
c |= 2; cout << "Line 11 - |= Operator, Value of c = : " <<c<< endl ;
return 0;}
Conditional operator Operator Example
() ? : a = 2;b = 9;c = (a>b) ? 2:7;Cout<<“c = ”<<c;Output :c = 7
ArraysIt is continuous memory of same data typesArray can be of int , float or charSyntax :
data_type variable_name[n]; where n is size of arrayFor example,int arry[5] ;
Initilization of arrayint a[3];a[0] = 0; a[1] = 1; a[2] = 3;
ORint a[3] = {0,1,2};
THANK YOU