1. Compound Assignment Operators in C++
Simple assignment operator Compound assignment operator
X = X + 1; X += 1;
Y = Y – 1 ; Y -= 1 ;
Z = Z + X ; Z += X ;
P = P * item ; P *= item ;
N = N * (x + 1) ; N *= (x + 1) ;
Total = Total / (X+Y); Total /= (X+Y);
Hours = Hours % 13; Hours %= 13;
Programming Fundamentals

2. Increment and Decrement Operators in C++
Increment Operators
Decrement Operators
1- Postfix operator: e.g. i++
2- Prefix operator: e.g. ++i
1- Postfix operator: e.g. i Prefix operator: e.g. --i
For postfix operators, the increment (or decrement) occurs after the current value of the variable has been used.
For prefix operators, the increment (or decrement) occurs first and the new value of the variable is then used.
Example
The following C++ statements has the effects as shown in the comment:
i = 3; // initial value of i
k = i++; // assigns 3 to k and 4 to i
k = ++i; // assigns 5 to k and 5 to i
k = i-- ; // assigns 5 to k and 4 to i
k = --i ; // assigns 3 to k and 3 to i
Programming Fundamentals

3. Increment and Decrement Operators
Simple
easy
easiest
x = x+1;
x += 1
x++
x = x-1;
x -= 1
x--
Programming Fundamentals

4. Programming Fundamentals
Example
Compute the following expression where: z=3, x=2, y=2
Z+= ++x - y--;
Solution:
Programming Fundamentals

5. Control Structures (Selections)
Topics to cover here:
Selection statements in the algorithmic language:
One-Way Selection
Two-Way Selection
Multi-Way Selection
Nested Structures
Selection statements in C++ language
Programming Fundamentals

6. Programming Fundamentals
Selections .. cont.
The selection statement allows to choose a set of statements for execution.
The selection depends on the validity of a condition when the program is executed.
The condition is a logical expression that has values as true or false.
Programming Fundamentals

7. One-Way Selection IF (condition) THEN statements END IF
Syntax:
In pseudo code
In C++
IF (condition) THEN
statements
END IF
if (logical expression)
statements;
The semantics (execution) of this statement:
If the value of the “condition” is true, the statements between IF .. END IF are executed and the execution continues to the statement after END IF.
If the value of the “condition” is false, the statements between IF .. END IF are ignored and the execution continues from the statement that follows END IF.
Programming Funamental slides
Programming Fundamentals 7

8. Programming Fundamentals
One-Way Selection
The following figure shows the execution of this selection statement.
Condition
false
true
statements
continue
Programming Fundamentals

9. One-Way Selection .. Examples
Write an algorithm that takes an integer and prints its double value if it is less than 50.
First, we have to analyze the problem to understand what is its requirements and how to solve it.
1- Analysis stage:
Problem Input:
- An integer, say n
Problem Output:
- The double value of n
Criteria
if n < 50, print its double value
Programming Fundamentals

10. Programming Fundamentals
Example 1 .. cont.
2- Algorithm Design
ALGORITHM Double
INPUT n
IF ( n < 50 ) THEN
OUTPUT “The double value is “ , n * 2
END IF
OUTPUT “ Finished”
END
Programming Fundamentals

11. Programming Fundamentals
Example 1 .. cont.
3- Testing the algorithm
n (n < 50)
true
The output:
The double value is 24
Finished
Programming Fundamentals

12. Programming Fundamentals
Example 1: C++ Program
#include <iostream>
using namespace std;
void main ( ) {
int n ;
cin >> n ;
if (n < 50)
cout << “The double value is “ << n * 2 << endl ;
cout << “ Finished “ << endl; }
Programming Fundamentals

13. Programming Fundamentals
Example 2
Write an algorithm that takes two integers and prints the smallest number. Use only one output statement.
1- Analysis stage:
Problem Input:
- Two integers, say num1 and num2
Problem Output:
- The smaller number
Criteria
Print the smaller number using only one output statement
Programming Fundamentals

14. Programming Fundamentals
Example 2 .. cont.
2- Algorithm Design
ALGORITHM Smallest
INPUT num1, num2
temp  num1
IF ( num2 < num1 ) THEN
temp  num2
END IF
OUTPUT “The smallest number is “ , temp
END Smallest
Programming Fundamentals

15. Programming Fundamentals
Example 2 .. cont.
3- Testing the algorithm
num1 num temp (num2<num1) 9
true 3
The output:
The smallest number is 3
Programming Fundamentals

16. Programming Fundamentals
Example 2: C++ Program
#include <iostream>
using namespace std;
void main ( ) {
int num1, num2, temp;
cin >> num1>>num2;
temp = num1;
if (num2 < num1)
temp = num2;
cout << “The smallest number is: “<< temp; }
Programming Fundamentals

17. Programming Fundamentals
Example 3
Write an algorithm that takes three integers and prints their average, if there summation is over 50.
1- Analysis stage:
Problem Input:
- Three integers, say n1, n2, n3
Problem Output:
- The average of the three numbers, or nothing
Criteria
Calculate the average only if the summation of the numbers is over 50.
Programming Fundamentals

18. Programming Fundamentals
Example 3.. cont.
2- Algorithm Design
ALGORITHM Average
INPUT n1, n2, n3
sum  n1 + n2 + n3
IF ( sum > 50 ) THEN
avg  sum / 3
OUTPUT “The average is: “, avg
END IF
END Average
Programming Fundamentals

19. Programming Fundamentals
Example 3 .. cont.
3- Testing the algorithm
n1 n n3 sum (sum>50) avg
210
true 70
The output:
The average is: 70
Programming Fundamentals

20. Programming Fundamentals
Example 3: C++ Program
#include <iostream>
using namespace std;
void main ( ) {
int n1, n2, n3, sum;
float avg;
cin >> n1>>n2>>n3;
sum = n1 + n2 + n3;
if (sum > 50)
avg = sum / 3.0;
cout << “The average is: “<< avg; }
Programming Fundamentals

21. Two-Way Selection IF (condition) THEN statements1 ELSE statements2
This statement chooses- statements to run- from two sets of choices.
Syntax:
In pseudo code
In C++
IF (condition) THEN
statements1
ELSE
statements2
END IF
if (logical expression)
statements1;
else
statements2;
Programming Funamental slides
Programming Fundamentals 21

22. Two-Way Selection .. cont.
The semantics (execution) of this statement:
If the value of the “condition” is true, the statements after THEN are executed and the execution continues to the statement after END IF.
If the value of the “condition” is false, the statements after ELSE are executed and the execution continues from the statement that follows END IF.
The following figure shows this execution:
Programming Fundamentals

23. Two-Way Selection .. cont.
condition
false
true
statements2
statements1
continue
Programming Fundamentals

24. Two-Way Selection .. Examples
Write an algorithm that takes two integers and prints the smallest number with appropriate message.
1- Analysis stage:
Problem Input:
- Two integers, say num1 and num2
Problem Output:
- The smaller number
Programming Fundamentals

25. Programming Fundamentals
Example 4 .. cont.
2- Algorithm Design
ALGORITHM Smaller
INPUT num1, num2
IF ( num1 < num2 ) THEN
OUTPUT “The smaller number is “ , num1
ELSE
OUTPUT “The smaller number is “ , num2
END IF
END Smaller
Programming Fundamentals

26. Programming Fundamentals
Example 4 .. cont.
3- Testing the algorithm
num1 num (num2<num1)
true
The output:
The smaller number is 3
Programming Fundamentals

27. Programming Fundamentals
Example 4: C++ Program
#include <iostream>
using namespace std;
void main ( )
{ int num1, num2 ;
cin >> num1 >> num2 ;
if ( num1 < num2 )
cout << “The smaller value is “ << num1 << endl ;
else
cout << “The smaller value is “ << num12 << endl ; }
Programming Fundamentals

28. Programming Fundamentals
Example 5
Write an algorithm that takes prices of two items, if there total is over 100 JDs, calculate a discount of 40% and tax of 16%. Otherwise, calculate a discount of 20% and tax of 6%. Then calculate the total price as: Total + tax – Discount.
1- Analysis stage:
Problem Input:
- Two prices, p1 and p2
Problem Output:
- The total price of the two items
Criteria
check whither the total prices is over 100 or not.
Programming Fundamentals

29. Programming Fundamentals
Example 5 .. cont.
2- Algorithm Design
ALGORITHM Total_Price
INPUT p1, p2
sub_total  p1 + p2
IF (sub_total > 100) THEN
Discount  sub_total * 0.4
Tax  sub_total * 0.16
ELSE
Discount  sub_total * 0.2
Tax  sub_total * 0.06
END IF
Total  sub_total + Tax - Discount
END Total_Price
Programming Fundamentals

30. Programming Fundamentals
Example 5: C++ Program
#include <iostream>
using namespace std;
void main ( )
{ float p1, p2, sub_total, discount, tax, total;
cin >> p1 >> p2;
sub_total = p1 + p2;
if ( sub_total > 100) {
discount = sub_total * 0.4;
tax = sub_total * 0.16; }
else
discount = sub_total * 0.2;
tax = sub_total * 0.06;
Programming Fundamentals

31. Programming Fundamentals
Multi Way Selection
You can choose statement(s) to run from many sets of choices.
There are two cases for this:
Multi way selection by nested IF structure
Multi way selection by SWITCH structure
Programming Fundamentals

32. Multi Way Selection by Nested IF Structure
The structure that contains another structure of the same type is called a nested structure.
In the Nested IF structure, the statements that exists between IF and ELSE or between IF and END IF can contain IF statement.
Programming Fundamentals

33. Multi Way Selection by Nested If Structure .. Cont.
Syntax of one possible structure:
IF (condition1) THEN
Statements1
ELSE IF (condition2) THEN
Statements2
ELSE IF (Condition3) THEN
Statements3
ELSE IF (Condition4) THEN
Statements4
END IF
Note: The nest can be to many levels.
The following figure shows the execution of this structure.
Programming Fundamentals

34. Multi Way Selection by Nested If Structure .. Cont.
Syntax:
In pseudo code
In C++
IF (condition1) THEN
Statements1
ELSE IF (condition2) THEN
Statements2
ELSE IF (Condition3) THEN
Statements3
ELSE IF (Condition4) THEN
Statements4
END IF
if (condition1)
Statements1;
else if (condition2)
Statements2 ;
else if(Condition3)
Statements3;
else if(Condition4)
Statements4;
Note: The nest can be to many levels.
Programming Funamental slides
Programming Fundamentals 34

35. Multi Way Selection by Nested If Structure .. Cont.
True
Condition1
Statements1
False
Condition2
True
Statements2
Rest of
algorithm
False
Condition3
True
Statements3
False
Statements4
Programming Fundamentals

36. Multi Way Selection by Nested If Structure .. Examples
Write an algorithm that inputs a student mark and outputs the corresponding grade, where grades are as follows:
mark grade A B C D
< 60 E
Programming Fundamentals

37. Programming Fundamentals
Example 4 .. Cont.
1- Analysis stage:
Problem Input:
- student’s mark, mark
Problem Output:
- grade
Criteria
- according to the previous grade table
Programming Fundamentals

38. Programming Fundamentals
Example 4 .. Cont.
2- Algorithm Design
ALGORITHM Grades
INPUT mark
IF ( mark < 0 OR mark > 100 ) THEN
OUTPUT “ Mark out of range”
ELSE IF ( mark  90 AND mark  100 ) THEN
OUTPUT “A”
ELSE IF ( mark  80 ) THEN
OUTPUT “B”
ELSE IF ( mark  70 ) THEN
OUTPUT “C”
ELSE IF ( mark  60 ) THEN
OUTPUT “D”
ELSE OUTPUT “E”
END IF
END Grades
Programming Fundamentals

39. Programming Fundamentals
Example 3: C++ Program
#include <iostream>
using namespace std;
void main ( )
{ int mark ;
cin >> mark;
if ( mark < 0 || mark > 100 )
cout << “ Mark out of range” << endl;
else if ( mark >= 90 )
cout << “A” << endl ;
else if ( mark >= 80 )
else if ( mark >= 70 )
cout << “C” << endl ;
else if ( mark >= 60 )
cout << “D” << endl ;
else cout << “E” << endl ; }
Programming Fundamentals

40. Comparison of Nested IF Structure and a Sequence of IF Structures
Some times the nested IF structure is a good solution for a given problem than a sequence of IF structures.
Consider the following example:
Nested case:
IF ( x > 0 ) THEN
pos_count  pos_count + 1
ELSE IF ( x < 0 ) THEN
neg_count  neg_count + 1
ELSE
zero_count  zero_count + 1
END IF
Programming Fundamentals

41. Comparison of Nested IF Structure and a Sequence of IF Structures
(b) Sequence case:
IF ( x > 0 ) THEN
pos_count  pos_count + 1
END IF
IF ( x < 0 ) THEN
neg_count  neg_count + 1
IF ( x = 0 ) THEN
zero_count  zero_count + 1
Programming Fundamentals

42. Comparison of Nested IF Structure and a Sequence of IF Structures
In the previous example, only one statement should be executed for any value of x.
In the sequence case, the sequence does not show clearly that exactly one of the three statements is executed for any value of x.
In the nested case, only one statement is executed exactly. Therefore, it is better than the sequence case.
Programming Fundamentals

43. Problem : Read three numbers to print the smallest one.
#include <iostream.h> void main() { int a, b, c; cout<<"\nPlease Enter three numbers:"; cin>>a>>b>>c; cout<<"\nMin= "; if ((a < b) && (a < c)) cout<<a; if ((b < a) && (b < c)) cout<<b; if ((c < a) && (c < b)) cout<<c; cout<<endl; }
Programming Fundamentals

44. Sorting via comparisons
Program2 (nested if)
a<b?
b<c?
c<b?
a b c
a<c?
c b a
c<a?
b a c
a c b
c a b
b c a

45. Programming Fundamentals
Program2 (nested if)
#include <iostream.h> void main() { int a, b, c; cout<<"\nPlease Enter three numbers:"; cin>>a>>b>>c; cout<<"\nMin= "; if (a < b) if (a < c) cout<<a; else cout<<c; else if (b < c) cout<<b; else cout<<c; cout<<endl; }
Programming Fundamentals

46. Programming Fundamentals
In Line Condition:
You can include an in-line condition within a cout command or in an assignment statement.
Example1:
cout << (x>100? “Large”:”Small”)
This is the same as the if condition:
if (x>100)
cout <<“Large”;
else
cout << “Small”
Programming Fundamentals

47. Programming Fundamentals
In Line Condition:
Example2:
int x, y;
cin >> y;
x = (y<0? -1:1);
This is the same as the if condition:
if (y<0)
x = -1;
else
x = 1;
Note here, that the result of the in-line condition, should match the data type of the variable at the left-hand side of the assignment statement
Programming Fundamentals

48. Programming Fundamentals
Note:
In the previous examples, we used logical or relational expressions as conditions for if statement, since they generate a result of Boolean data types.
In some cases, you may need to use a variable as the condition of an if statement. But, how this variable will be interpreted into the result of the condition?
We can use: If(x)
Programming Fundamentals

49. Programming Fundamentals
Example: {
int x;
cin>> x;
if (x)
cout << “x is any number but zero”;
else
cout << “ x is zero”; }
Notes: - a value of 0, is considered false in this case, while all other values, either positive or negative, are considered true.
The same applies for float variables.
Character variables always return true.
Programming Fundamentals

50. Programming Fundamentals
Note:
cin is used within the if condition, to check wither the user enters a number or a character. If the user enters a number, it will be considered true, and print the first output message. While if the user enters character, it will be considered false, and print the second output message.
The same applies with the float variables.
This technique is used to make sure the user enters a number in such variables, and forbid him/her from entering characters instead.
Programming Fundamentals

51. Programming Fundamentals
Example:
Check this example:
void main () {
int x;
if (cin >> x)
cout << "number";
else
cout << "character"; }
Programming Fundamentals

52. Switch Statement in C++

53. Switch Statement in C++
Syntax
switch (selector)
{ case L1: statements1; break;
case L2: statements2; break; …
default: statements_n; }
Semantics:
This statement has the same meaning as in the algorithmic language.

54. Example 1: C++ Program void main ( ) { int lab; cin >> lab;
#include <iostream>
using namespace std;
void main ( ) {
int lab;
cin >> lab;
switch ( lab )
case 503 : cout << “ C++ “ << endl; break;
case 508: cout << “ C# “ << endl; break;
case 512 : cout << “ Oracle “ << endl; break;
case 514: cout << “ PHP “ << endl; break;
case 507: cout << “ Java “ << endl; break;
default : cout << “ MS Office “ << endl; }

55. Example 2: C++ Program cin >> ch ; switch ( ch )
#include <iostream>
using namespace std;
void main ( )
{ char ch ;
cin >> ch ;
switch ( ch )
{ case ‘c’ : cout << “ do “ << endl; break;
case ‘d’ : cout << “ re “ << endl; break;
case ‘e’ : cout << “ mi “ << endl; break;
case ‘f’ : cout << “ f “ << endl; break;
case ‘g’ : cout << “ sol “ << endl; break;
case ‘a’ : cout << “ la “ << endl; break;
case ‘b’ : cout << “ ti “ << endl; break;
default : cout << “ Invalid note was read “ << endl; }

56. Example 3: C++ Program #include <iostream> using namespace std;
void main ( )
{ char ch ;
cout << “ \n Enter the grade of student: “<<endl ;
cin >> ch;
switch (ch) {
case ‘A’ :
case ‘a’ :
cout<<”Excellent”;
break;
case ‘B’ :
case ‘b’ :
cout<<”Good”;
case ‘C’ :
case ‘c’ :
cout<<”O.K”;
case ‘D’ :
case ‘d’ :
case ‘F’ :
case ‘f’ :
cout<<”poor”;
default: cout<<”invalid letter grade”; } }

57. Flow Chart of switch statement
switch (grade)
case ‘A’ : case ‘a’ :
Display
“Excellent”
case ‘B’ : case ‘b’ :
Display
“Good” …
Default :
“……..”

58. Example 4: C++ Program void main() { int x,y;
#include <iostream>
using namespace std;
void main()
{ int x,y;
cout << "Enter 2 integer number: ";
cin >> x>>y;
switch (x+y)
{ case 7: cout << "Too small, sorry!";
break;
case 5: cout << "Good job!\n";
case 4: cout << "Nice Pick!\n";
case 3: cout << "Excellent!\n";
case 2: cout << "Masterful!\n";
case 1: cout << "Incredible!\n";
default: cout << "Too large!\n"; }
cout << "\n\n";

59. Example 5: C++ Program #include <iostream> using namespace std;
void main ( )
{ char ch ; float radius, area, circum;
cout << “ Enter the radius of a circle: “ ;
cin >> radius;
cout << “ Enter a to calculate the area of a circle or c to calculate its circumference:”
cin >> ch ;
switch (ch)
{ case ‘a’ : area = 3.14f * radius * radius;
cout << “ Area = “ << area << endl; break;
case ‘c’ : circum = 2 * radius * 3.14f ;
cout << “ Circumference = “ << circum << endl; break;
default : cout << “ Invalid letter was read “ << endl; }

60. Convert Switch into IF #include <iostream> using namespace std;
Rewrite Example 3, using IF instead of Switch:
#include <iostream>
using namespace std;
void main ( )
{ char ch ;
cout << “ \n Enter the grade of student: “<<endl ;
cin >> ch;
if (ch == ‘A’ || ch == ‘a’)
cout<<”Excellent”;
else
if (ch == ‘B’ || ch == ‘b’)
cout<<”Good”;
if (ch == ‘C’ || ch == ‘c’)
cout<<”O.K”;
if (ch == ‘D’ || ch == ‘d’ || ch == ‘F’ || ch == ‘f’)
cout<<”poor”;
cout<<”invalid letter grade”; }

61. Convert IF into Switch – Example 6
#include <iostream> using namespace std; void main ( ) { char degree; cout << “ \n Enter the temperature degree “<<endl ; cin >> degree; if (degree >= 50) cout<<”Very Hot”; else if (degree >= 35 && degree <50) cout<<”Hot”; else if (degree >= 20 && degree <35) cout<<”Fair”; else if (degree >= 0 && degree <20) cout<<”Cold”; else cout<<”Very Cold”; }
#include <iostream> using namespace std; void main ( ) { char degree; cout << “ \n Enter the temperature degree “<<endl ; cin >> degree; switch (degree >= 50) { case true: cout<<”Very Hot”; break; case false: switch (degree >= 35 && degree <50) case true: cout<<”Hot”; break; switch (degree >= 20 && degree <35) case true: cout<<”Fair”; break; switch (degree >= 0 && degree <20) case true: cout<<”Cold”; break; case false: cout<<”Very Cold”; } } } }