Numeric Data Types

Integral Types

char, short, int, long

Integer values can be positive or negative, unless they are explicitly declared as unsigned, in which case, they can only be positive.

char

short

int

long

More Numeric Types

Floating-Point Types

float, double, long double

Floating-point types are used to represent real numbers and have both integer and fractional parts. They can also have exponents.

float

double

long double

Declarations for Numeric Types

Named Constant Declarations

const float PI = 3.14159;

const float E = 2.71828;

const int MAX_SCORE = 100;

const int MIN_SCORE = -100;

Variable Declarations

int studentCount; // Number of students

int sumOfScores; // Sum of their scores

float average; // Average of the scores

Appropriate Assignments

average = 95.7;

sumOfScores = 2478;

Arithmetic Operators

+ Unary plus (one operand)

- Unary minus (one operand)

+ Addition (two operands)

- Subtraction (two operands)

* Multiplication (two operands)

/ Floating-point division (floating-point result)

Integer division (no fractional part)

% Modulus (remainder from integer division) (two operands)

6/2 = 3 7/2 = 3

6 % 2 = 0 7 %2 = 1

Example Expressions

Expression Value

3 + 6 9

Example Expressions

Expression Value

3 + 6 9

3.4 – 6.1 -2.7

Example Expressions

    Expression Value

3 + 6    9

3.4 – 6.1 -2.7

2 * 3    6

Example Expressions

    Expression Value

3 + 6    9

3.4 – 6.1 -2.7

2 * 3    6

8/2    4

Example Expressions

    Expression Value

3 + 6    9

3.4 – 6.1 -2.7

2 * 3    6

8/2    4

8.0/2.0    4.0

Example Expressions

    Expression Value

3 + 6    9

3.4 – 6.1 -2.7

2 * 3    6

8/2    4

8.0/2.0    4.0

8/8    1

Example Expressions

    Expression Value

3 + 6    9

3.4 – 6.1 -2.7

2 * 3    6

8/2    4

8.0/2.0    4.0

8/8    1

8/9    0

Example Expressions

    Expression Value

3 + 6    9

3.4 – 6.1 -2.7

2 * 3    6

8/2    4

8.0/2.0    4.0

8/8    1

8/9    0

8/7    1

Example Expressions

    Expression Value

3 + 6    9

3.4 – 6.1 -2.7

2 * 3    6

8/2    4

8.0/2.0    4.0

8/8    1

8/9    0

8/7    1

8 % 8    0

Example Expressions

    Expression Value

3 + 6    9

3.4 – 6.1 -2.7

2 * 3    6

8/2    4

8.0/2.0    4.0

8/8    1

8/9    0

8/7    1

8 % 8    0

8 % 9    8

Example Expressions

    Expression Value

3 + 6    9

3.4 – 6.1 -2.7

2 * 3    6

8/2    4

8.0/2.0    4.0

8/8    1

8/9    0

8/7    1

8 % 8    0

8 % 9    8

8 % 7    1

Example Expressions

    Expression Value

3 + 6    9

3.4 – 6.1 -2.7

2 * 3    6

8/2    4

8.0/2.0    4.0

8/8    1

8/9    0

8/7    1

8 % 8    0

8 % 9    8

8 % 7    1

0 % 7    0

Example Expressions

    Expression Value

3 + 6    9

3.4 – 6.1 -2.7

2 * 3    6

8/2    4

8.0/2.0    4.0

8/8    1

8/9    0

8/7    1

8 % 8    0

8 % 9    8

8 % 7    1

0 % 7    0

5 % 2.3    Error

Assignment Statements

Given int num; int alpha;

float rate; char ch;

Valid Assignments

alpha = num + 6;

alpha = num / 2;

num = alpha * 2;

alpha = alpha + 1;

num = num + alpha;

Program Example

//************************************************************

// FreezeBoil program

// This program computes the midpoint between

// the freezing and boiling points of water

//************************************************************

#include <iostream>

using namespace std;

const float FREEZE_PT = 32.0; // Freezing point of water

const float BOIL_PT = 212.0; // Boiling point of water

Program Example (continued)

int main()

{

    float avgTemp;            // Holds the result of averaging

                              //   FREEZE_PT and BOIL_PT

    cout << "Water freezes at " << FREEZE_PT << endl;

    cout << " and boils at " << BOIL_PT << " degrees." << endl;

    avgTemp = FREEZE_PT + BOIL_PT;

    avgTemp = avgTemp / 2.0;

    cout << "Halfway between is ";

    cout << avgTemp << " degrees." << endl;

    return 0;

}

Increment and Decrement Operators

++ Increment

-- Decrement

num++; is equivalent to num = num + 1;

IncrementStatement Decrement Statement

Compound Arithmetic Expressions

Precedence Rules

Highest: Unary +, Unary –, Parentheses

Middle *, /, %

Lowest +, -

Associativity is from left to right

int1 – int2 + int3

is evaluated

(int1 – int2) + int3

Precedence Examples

Expression Value

10 / 2 * 3

Precedence Examples

Expression Value

10 / 2 * 3 = 5 * 3

Precedence Examples

Expression Value

10 / 2 * 3 = 5 * 3 = 15

Precedence Examples

Expression Value

10 / 2 * 3 = 5 * 3 = 15

10 % 3 – 4 / 2

Precedence Examples

Expression Value

10 / 2 * 3 = 5 * 3 = 15

10 % 3 – 4 / 2 = 1 – 2

Precedence Examples

Expression Value

10 / 2 * 3 = 5 * 3 = 15

10 % 3 – 4 / 2 = 1 – 2 = -1

Precedence Examples

Expression Value

10 / 2 * 3 = 5 * 3 = 15

10 % 3 – 4 / 2 = 1 – 2 = -1

5.0 * 2.0 / 4.0 * 2.0

Precedence Examples

Expression Value

10 / 2 * 3 = 5 * 3 = 15

10 % 3 – 4 / 2 = 1 – 2 = -1

5.0 * 2.0 / 4.0 * 2.0

= 10.0 /4.0 *2.0

Precedence Examples

Expression Value

10 / 2 * 3 = 5 * 3 = 15

10 % 3 – 4 / 2 = 1 – 2 = -1

5.0 * 2.0 / 4.0 * 2.0

= 10.0 /4.0 *2.0

= 2.5 * 2.0

Precedence Examples

Expression Value

10 / 2 * 3 = 5 * 3 = 15

10 % 3 – 4 / 2 = 1 – 2 = -1

5.0 * 2.0 / 4.0 * 2.0

= 10.0 /4.0 *2.0

= 2.5 * 2.0 = 5.0

Precedence Examples

Expression Value

10 / 2 * 3 = 5 * 3 = 15

10 % 3 – 4 / 2 = 1 – 2 = -1

5.0 * 2.0 / 4.0 * 2.0

= 10.0 /4.0 *2.0

= 2.5 * 2.0 = 5.0

5.0 * 2.0 / (4.0 * 2.0)

Precedence Examples

Expression Value

10 / 2 * 3 = 5 * 3 = 15

10 % 3 – 4 / 2 = 1 – 2 = -1

5.0 * 2.0 / 4.0 * 2.0

   = 10.0 /4.0 *2.0

   = 2.5 * 2.0 = 5.0

5.0 * 2.0 / (4.0 * 2.0)

   = 10.0 / 8.0

Precedence Examples

Expression Value

10 / 2 * 3 = 5 * 3 = 15

10 % 3 – 4 / 2 = 1 – 2 = -1

5.0 * 2.0 / 4.0 * 2.0

   = 10.0 /4.0 *2.0

   = 2.5 * 2.0 = 5.0

5.0 * 2.0 / (4.0 * 2.0)

   = 10.0 / 8.0 = 1.25

Precedence Examples

Expression Value

10 / 2 * 3 = 5 * 3 = 15

10 % 3 – 4 / 2 = 1 – 2 = -1

5.0 * 2.0 / 4.0 * 2.0

   = 10.0 /4.0 *2.0

   = 2.5 * 2.0 = 5.0

5.0 * 2.0 / (4.0 * 2.0)

   = 10.0 / 8.0 = 1.25

5.0 + 2.0 / (4.0 * 2.0)

Type Coercion
(Implicit Conversion)

Integer values and floating-point values are stored differently inside a computer’s memory.

Consider the declarations:

int someInt;

float someFloat;

and the assignments:

someFloat = 12;

someInt = 4.8;

What actually occurs is

someFloat = 12.0

someInt = 4

Type Casting
(Explicit Coercion)

A C++ cast operation consists of a data type name and then, within parentheses, the expression to be converted:

someFloat = float (3 * someInt + 2);

someInt = int (5.2 / someFloat – anotherFloat);

Countless errors have resulted from unintentional mixing of types.

It’s possible to mix data types within an expression.

Mixed Type Expression Evaluation

Whenever an integer value and a floating-point value are joined by an operator, implicit type coercion occurs as follows.

The integer value is temporarily coerced to a floating-point value.

The operation is performed.

The result is a floating-point value.

Consider int sum; int count; float average;

and average = sum / count;

average will have the value 0.0

if sum = 60 and count = 80

Function Calls

The following C++ statement has a call to the function Square in it:

cout << “27 squared is” << Square(27);

The function call consists of the symbols

Square(27)

and may also be called a function invocation.

The computer temporarily puts the main function on hold and starts the Square function running.

When the Square function has finished doing its work, the computer goes back to main and picks up where it left off.

More About Function Calls

In the above function call, the number 27 is known as an argument (or actual parameter). Arguments make it possible for the same function to work on many different values.

Syntax Template

FunctionName ( ArgumentList )

The argument list is a way for functions to communicate with each other. There can be from zero to many arguments in the list.

The Last Words on
Function Calls For Now

Value-returning functions

The function call is used within an expression; it does not appear as a separate statement.

The function computes a value (result) that is then available for use in the expression.

The function returns exactly one result – no more, no less.

The argument to a value-returning function can be any expression of the appropriate type.

The compiler applies type coercion if the types don’t match.

Library Functions

Every C++ system includes a large set of prewritten (library) functions.

To use a function call, place an #include directive near the top of your program, specifying the appropriate header file, then make the call.

Library Function Example

Example:

#include <iostream>

#include <cmath> // For sqrt() and fabs()

using namespace std;

.

.

.

float alpha;

float beta;

.

.

.

alpha = sqrt(7.3 + fabs(beta));

Void Functions

A void function doesn’t return a function value, it just performs some action and then quits.

With a void function, the function call is a separate, stand-alone statement.

Example call from payroll program

CalcPay (payRate, hours, wages);


	Integral Types
		char, short, int, long
		Integer values can be positive or negative, unless they are explicitly declared as unsigned, in which case, they can only be positive.

		char
		short
		int
		long


	Floating-Point Types
		float, double, long double
		Floating-point types are used to represent real numbers and have both integer and fractional parts. They can also have exponents.

		float
		double
		long double


	Named Constant Declarations
		const float PI = 3.14159;
		const float E = 2.71828;
		const int MAX_SCORE = 100;
		const int MIN_SCORE = -100;
	Variable Declarations
		int studentCount; // Number of students
		int sumOfScores; // Sum of their scores
		float average; // Average of the scores
	Appropriate Assignments
	average = 95.7;
	sumOfScores = 2478;


+ Unary plus (one operand)
	- Unary minus (one operand)
	+ Addition (two operands)
	- Subtraction (two operands)
	* Multiplication (two operands)
	/ Floating-point division (floating-point result)
		Integer division (no fractional part)
	% Modulus (remainder from integer division) (two operands)
	6/2 = 3 7/2 = 3
	6 % 2 = 0 7 %2 = 1


	Expression Value
	3 + 6 9
	3.4 – 6.1 -2.7
	2 * 3 6
	8/2 4
	8.0/2.0 4.0


	Given int num; int alpha;
	float rate; char ch;
	Valid Assignments
		alpha = num + 6;
		alpha = num / 2;
		num = alpha * 2;
		alpha = alpha + 1;
		num = num + alpha;


	//************************************************************
	// FreezeBoil program
	// This program computes the midpoint between
	// the freezing and boiling points of water
	//************************************************************

	#include <iostream>

	using namespace std;

	const float FREEZE_PT = 32.0; // Freezing point of water
	const float BOIL_PT = 212.0; // Boiling point of water


	int main()
	{
	float avgTemp; // Holds the result of averaging
	// FREEZE_PT and BOIL_PT

	cout << "Water freezes at " << FREEZE_PT << endl;
	cout << " and boils at " << BOIL_PT << " degrees." << endl;

	avgTemp = FREEZE_PT + BOIL_PT;
	avgTemp = avgTemp / 2.0;

	cout << "Halfway between is ";
	cout << avgTemp << " degrees." << endl;

	return 0;
	}


	++ Increment
	-- Decrement
	num++; is equivalent to num = num + 1;
	IncrementStatement Decrement Statement


	Precedence Rules
		Highest: Unary +, Unary –, Parentheses
		Middle *, /, %
		Lowest +, -
	Associativity is from left to right
		int1 – int2 + int3
		is evaluated
		(int1 – int2) + int3


	Expression Value
	10 / 2 * 3 = 5 * 3 = 15
	10 % 3 – 4 / 2 = 1 – 2


	Expression Value
	10 / 2 * 3 = 5 * 3 = 15
	10 % 3 – 4 / 2 = 1 – 2 = -1


	Integer values and floating-point values are stored differently inside a computer’s memory.
	Consider the declarations:
		int someInt;
		float someFloat;
	and the assignments:
		someFloat = 12;
		someInt = 4.8;
	What actually occurs is
		someFloat = 12.0
		someInt = 4


	A C++ cast operation consists of a data type name and then, within parentheses, the expression to be converted:
		someFloat = float (3 * someInt + 2);
		someInt = int (5.2 / someFloat – anotherFloat);
	Countless errors have resulted from unintentional mixing of types.
	It’s possible to mix data types within an expression.


	Whenever an integer value and a floating-point value are joined by an operator, implicit type coercion occurs as follows.
		The integer value is temporarily coerced to a floating-point value.
		The operation is performed.
		The result is a floating-point value.
	Consider int sum; int count; float average;
	and average = sum / count;
	average will have the value 0.0
	if sum = 60 and count = 80


	The following C++ statement has a call to the function Square in it:
	cout << “27 squared is” << Square(27);
	The function call consists of the symbols
	Square(27)
	and may also be called a function invocation.
	The computer temporarily puts the main function on hold and starts the Square function running.
	When the Square function has finished doing its work, the computer goes back to main and picks up where it left off.


	In the above function call, the number 27 is known as an argument (or actual parameter). Arguments make it possible for the same function to work on many different values.
	Syntax Template
		FunctionName ( ArgumentList )
	The argument list is a way for functions to communicate with each other. There can be from zero to many arguments in the list.


	Value-returning functions
		The function call is used within an expression; it does not appear as a separate statement.
		The function computes a value (result) that is then available for use in the expression.
		The function returns exactly one result – no more, no less.
	The argument to a value-returning function can be any expression of the appropriate type.
	The compiler applies type coercion if the types don’t match.


	Every C++ system includes a large set of prewritten (library) functions.
	To use a function call, place an #include directive near the top of your program, specifying the appropriate header file, then make the call.


	Example:
		#include <iostream>
		#include <cmath> // For sqrt() and fabs()

		using namespace std;
		.
		.
		.
		float alpha;
		float beta;
		.
		.
		.
		alpha = sqrt(7.3 + fabs(beta));


	A void function doesn’t return a function value, it just performs some action and then quits.
	With a void function, the function call is a separate, stand-alone statement.
	Example call from payroll program
		CalcPay (payRate, hours, wages);