The document discusses input and output statements in C++. It explains that the iostream library includes cout and cin for standard output and input. cout uses the insertion operator << to output data to the screen, while cin uses the extraction operator >> to input data from the keyboard. The document provides examples of using cout and cin to output text, numbers, and calculate values from user input.

1. FP 201 – Programming
Fundamentals
Operators & Expressions

2. Learning outcome
By the end of the course, students should be able to:
Define the following operators:
a. Arithmetic operator
b. Assignment operator
c. Increment and decrement operator
d. Relational operator
e. Logical operator
Explain operators’ precedence
Explain type conversion
Write expression using operator
Use expression in program

3. Operators
Operator Action
- subtraction (also unary minus)
+ addition
* multiplication
/ division
% modulus division
-- decrement
++ increment
&& AND
|| OR
! NOT

4. Operators
Is a symbol that instructs compiler to perform an operation
or action.

5. Arithmetic Operators
Perform four fundamental operations which are addition,
subtraction, multiplication and division.
Operator Description Example Result
* Multiplication 2*8 16
/ Division 8/2 4
+ Addition 2+8 10
- Subtraction 8-2 6
() Parentheses. For grouping (8+2) 10
% Modulus. Divides two number and 4%3 1
returns just the remainder portion

6. Arithmetic Operators
arithmetic expressions are evaluated with some rule called
operator precedence.
multiplications (*) and divisions (/) are evaluated first
additions (+) and subtractions (-) are performed last.

7. Activity 1
Write the resultant value of the following expressions.
Expression Result
14-4
14+4
14* 4
14/4
14%4

8. ACTIVITY 2
Calculate the total marks for the given five subjects.
Declare appropriate variables, assign values as given
below:
English = 85
Maths = 100
History = 75
Geography = 70
Art = 85
 calculate the total marks
 calculate the average

9. #include<iostream>
using namespace std;
int main()
{
int english = 85, maths = 100, history = 75, geography = 70, art = 85;
int sum=0;
sum=english+maths+history+geography+art;
cout<<"Sum is: "<<sum<<endl;;
return 0;
}

10. #include<iostream>
using namespace std;
int main()
{
int english = 85, maths = 100, history = 75, geography = 70, art = 85;
int sum=0, average=0;
sum=english+maths+history+geography+art;
average=sum/5;
cout<<"Sum is: "<<sum<<endl;
cout<<"Average is:"<<average<<endl;
return 0;
}

11. Assignment Operator
variables are given a value through the use of assignment
operator (=)
general form:
variable = expression;
eg:
int x, y;
x = 2;
y = 5*x; // y = 10
x = x + 4; // x = 6
y = y/2; // y = 5

12. Assignment Operator
The value of an assignment can be used in another
assignment.
This is a chained assignment.
Eg:
m = (n = 66) + 9; // n = 66 and m = 75
x = y = 22; // x = 22 and y = 22

13. Compound Assignment Operators
(+=), (-=), (*=), (/=), (%=)
allow us to use assignment and an arithmetic operator
together.
general form is:
variable operator= expression;

14. Compound Assignment Operators
Operator Description Example Equivalent to
+= add and assign x += 3 x=x+3
-= subtract and assign x -= 5 x=x-5
*= multiply and assign x *= 4 x=x*4
/= divide and assign x /= 2 x=x/2
%= find reminder and assign x %= 9 x=x%9

15. In Class Exercise
 Given the following declaration and initial assignment:
int i = 4, j = 21, k;
float x = 94.55, y;
char a = ‘z’, b = ‘t’, c =‘ ‘;
Determine the value for the following assignments:
 k=i*j
y = x + i
y = k = j
 a = b =c
 i += i

16. Increment & Decrement Operator
increment operator (++) and decrement operator (--)
increase or reduce by one the value stored in a variable.
the following are equivalent in functionality.
x++;
x += 1;
x = x + 1;
characteristic of this operator:
can be used both as a prefix and as a postfix.
eg: a++ or ++a
the results is different

17. Prefix
When a prefix expression (++x or --x) is used as part
of an expression, the value returned is the value
calculated after the prefix operator is applied
int x = 0;
int y = 0;
y = ++x;
// result: y=1, x=1 x is incremented by 1 and the result is
assigned to y

18. Postfix
When a postfix expression (x++ or x--) is used as part
of an expression, the value returned is the value
calculated before the postfix operator is applied
int x = 0;
int y = 0;
y = x++;
// result: y=0, x=1 original value of x is stored, x is
incremented, original value of x is assigned to y

19. Increment & Decrement Operator
eg:
a = 5; // a = 5
b = a++; // b = a = 5, then a = 5+1 = 6
c = ++a; // a = 6+1 = 7, then c = a = 7

20. Relational Operator
 Control statements use relation operators in order to compare two objects,
which results in a value that is either true (1) or false (0).
 There are six relational operators as follows:
Operator Description Example Value
< less than x<y 6<9 1
<= less than or equal to x <= y 12 <= 13 1
> greater than x>y 7 > 10 0
>= greater than or equal to x >= y 9 >= 5 1
== equal to x == y 7 ==5 0
!= not equal to x != y 6 != 5 1

21. Logical Operator
Operator Description Example
logical AND, conjunction.
&& Both sides must be true for the result to x > 2 && y == 3
be true
logical OR, disjunction.
|| The result is true if either side or both x > 2 || x <= 9
sides are true.
! logical NOT, negation !(x>0)

22. Condition1 Condition2 && ||
true true true true
true false false true
false true false true
false false false false

23. Logical Operator
using these operators, we can form a Boolean Expression that
can be either true or false.
Boolean expressions evaluate to integer values.
The value 0 means 'false' and all non-zero value means 'true'.
There are also two literal constants used with bool
variables: true and false.

24. In Class Exercise
What is the difference between x = 3 and x == 3?
Given a = 2, b = 5, c = 7 determine the value for the
following expressions either TRUE or FALSE: :
1. a < 2 && b > 5
2. c >= a
3. a < b || b > c
4. c != 10
5. a == 25

25. Operator Precedence
Determines the order in which mathematical computations
and operations are performed in an expression.

26. Operator Precedence

27. Operator Precedence
Given a=b = 5, c = 2; solve the following expression
a+b*2/c–5
=5+5*2/2–5
= 5 + 10 / 2 – 5
=5+5–5
= 10 – 5
=5

28. In Class Exercise
Given x = 10, y = 7, z = 2; solve the following expression
x + 2y – z
x / z – x * x + y
x * y % z
5 ( x + y + z ) – x / z
++x*y – y*z

29. Type conversion/Type Casting
Is the conversion of a value of one data type into another
data type.
Typecasting consist of two types:
 Implicit conversion
 Explicit conversion

30. Implicit conversion
A value of data type with lower range is assigned to a variable
of data type with higher range
Lower range to higher range

31. Example
#include<iostream>
using namespace std;
OUTPUT
void main() Result: 4.2555
{
double x; // Size is 8 bytes
int y=2; //Size is 4 bytes
float z=2.2555f;
x=y+z; //Implicit conversion
cout<<"Result: "<<x;
}

32. Explicit conversion
A value of data type with higher range is assigned to a
variable of data type with lower range
Higher range to lower range
Explicit conversion leads to data loss.

33. Example
#include<iostream>
using namespace std;
OUTPUT
void main() The total value is:300
{
int total_value;
double book1 = 300.46;
total_value=(int)book1; // Explicit conversion
cout<<"The total value is:"<<total_value;
}

34. Exercise
Write a program to declare a variable d of type double.
Assign the value 102.5789 to d. Declare a float variable fl.
Assign the value of d to fl by performing an explicit
conversion and print the value on the screen.

35. Answer
#include<iostream>
using namespace std;
void main() OUTPUT
{ Value of the float variable fl = 102.579
double d=102.5789;
float fl;
fl=(float)d; // Explicit conversion
cout<<"Value of the float variable fl = "<<fl;
}

36. Summary
In this presentation, you learnt the following:
Operator is a symbol that instructs compiler to perform an
operation or action.
Typecasting is the conversion of data type of the value of a
variable into another.
There are two types of casting: implicit conversion and
explicit conversion.

37. FP 201 – Programming
Fundamentals with C++
Input Output Statements

38. Learning outcome
By the end of the course, students should be able to:
Identify the syntax use for input and output
Write program that use the input and output statements

39. Input/Output Statements
The standard C++ library includes the header file
iostream, where the standard input and output stream
objects are declared.
cout to output data to the screen and
cin to input data from the keyboard.

40. Standard Output
standard output:
need to use cout, followed by the insertion operator (<<)
eg:
cout << "Hello World!"; // Outputs "Hello World!"
on the screen
cout << 1299; // Outputs the number 1299 on the
screen
cout << x; // Outputs the content of x on the
screen
insertion operator (<<) may be used more than once in a
single statement:
cout << "Hi, " << "this is " << "a simple C++ statement";

41. Standard Output
Note that, cout does not add a line break.
For example:
cout << "Computer Programming ";
cout << "is important for engineers.";
will be output as:
Computer Programming is important for
engineers.

42. Standard Output
A line break can be added by inserting a 'n' character or a
using a endl manipulator.
cout << "Computer Programming n";
cout << "is important for engineers.";
cout << "Computer Programming " << endl;
cout << "is important for engineers.";
These two produce the following (same) output: Computer
Programming
is important for engineers.

43. Standard Input
 Handling the standard input is done by applying the
overloaded operator of extraction (>>) on the cin stream
 Value can be input from the keyboard and assigned to a
variable x as follows:
cin >> x;
 and two variables can assigned as any of the follows:
cin >> x;
cin >> y;
cin >> x >> y;

44. Code Example
// Calculates the sum of two integers
#include <iostream>
using namespace std;
int main()
{
int a, b, total;
cout << "Enter two integers to be added: ";
cin >> a >> b;
total = a + b;
cout << "The sum is " << total << endl;
return 0;
}

45. Code Example
// Calculates the area of a triangle
// given an input of the triangle base and height.
#include <iostream>
int main()
{
float base, height, area;
std::cout << "Enter the base and height of the
triangle: ";
std::cin >> base >> height;
area = 0.5*base*height;
std::cout << "The area of the triangle is "
<< area << std::endl;
}

46. Q&A
Develop a program that can calculate the total and average of
four numbers that is input by user.

47. #include <iostream>
using namespace std;
int main()
{
int a, b, c, d, total, average;
cout << "Enter four integers to be added: ";
cin >> a >> b>>c>>d;
total = a + b + c + d;
average = total/4;
cout << "The sum is " << total << endl;
cout<< "The average is "<< average << endl;
return 0;
}

48. Summary
In this presentation, you learnt the following:
cout to output data to the screen
cin to input data from the keyboard.
cout use insertion operator (<<)
cin use overloaded operator of extraction (>>)