1. DTI2143 Computer Programming 1 Chapter 3 Expression & Operators

4. 4 Introduction to Expression Process involves in money withdrawal scenario balance – withdrawed money = current balance Expression in C : bakiTerkini =wangKeluar – bakiSemasa;

5. What is Expression? 5 Introduction to Expression Combination or more than one variable or Constant (operand) which separated by operator Expression Operator example x + 3 - z Operand Consists of arithmetic relational logical

6. 6 Arithmetic Expression Known as Arithmetic Expression Mathematic Expression using Arithmetic Operator Represents by Represents by Unary operator Binary operator

7. Unary Operator 7 Arithmetic Expression Unary Operator Operates for one operand Computer memory cell example -20 a = -20; a b = +15; b +15

8. Unary Operator 8 Arithmetic Expression Example 1: int A = 5; ++A; printf(“%d”, A); output ? A--; printf(“%d”,A); output ? A++; printf(“%d”,A); output ?

9. Unary Operator 9 Arithmetic Expression Example 2: int A ; A=6; printf(“%d”,3 + --A); output ? printf(“%d”, A); output ? A=6; printf(“%d”, 3 + A--); output ? printf(“%d”, A); output ?

10. Unary Operator 10 Arithmetic Expression Example 3: Given the value of num1 = 8 .Determine the value of num2 after the execution for each of the following statements: num2 = num1++ - 2; num2 = num1; num2 = ++num1 – 3; num2 = num1-- +1;

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12. Binary Operator 12 Arithmetic Expression Located between constants or variables or both combination Binary Operator example A+ z operator operand

13. Binary Operator 13 Arithmetic Expression Multiplication Use symbol “ * ” example A * z operator operand Mathematic Arithmetic Expression 2x + y 2 * x + y

14. Binary Operator 14 Arithmetic Expression Divide Use symbol “/” example A / z operator operand Mathematic Arithmetic Expression 2 : y 2 / y

15. Binary Operator 15 Arithmetic Expression Modulus Use symbol “%” example A % z operator operand Return a balance when 2 numbers is divided Can only be used with an integer variable

16. Binary Operator 16 Arithmetic Expression Example: int A, B; float C; A= 2; B= 5; C= 2.4; B% A; C % A; Valid! Answer is 1 Invalid! C is float

18. Use operator symbol =Assignment statement Double assignment statement Compound assignment statement

21. Example :int a = b= c = d = e = 250; int b =2, number =0, total = 0,average =3; number = b++ = 10; int age = workHour = 0;

23. To simplify arithmetic operator

24. Original function of operator does not affected

25. Allowed combination are as follow:operator: += , -= , *= , /= , %=

26. Compound Assignment Statement 21 Arithmetic Expression Example :

27. Arithmetic Operator Precedence Rules 22 Arithmetic Expression Compiler will follows the following precedence to execute the arithmetic expression based on priority.

28. Arithmetic Operator Precedence Rules 23 Arithmetic Operator Example: 5 + 2 * 6 – 4 / 2 5 + 12 - 4 / 2 5 + 12 - 2 17 - 2 15 2. 3 * 4 / 2 + ( 3 –1) 3 * 4 / 2 + 2 12 / 2 + 2 6 + 2 8

29. Arithmetic Operator Precedence Rules 24 Arithmetic Expression Example: 3. Prefix unary arithmetic expression intkira = 5, nilaipertama = 10; nilai_kedua = 5 * --kira + nilai_pertama; printf(“%d %d”, kira, nilai_kedua); Output: 4 30

30. Arithmetic Operator Precedence Rules 25 Arithmetic Expression Example: 3. Prefix unary arithmetic expression int kira = 5, nilai pertama = 10; nilai_kedua = 5 * kira-- + nilai_pertama; printf(“%d %d”, kira, nilai_kedua); Output: 4 35

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34. Exercise: 28 Arithmetic Expression Convert the following mathematic expression to a valid arithmetic expression : a) b = 3 + bb) x = (a – b)(a – c2) a + 4 c) d = (3e – d) - ( 4 – 3c3 ) d) r = 2s + 3(s – 9) x – 9 4y s Given a= 3, b = 5, c=1. What is the output of the following expression? a. ( 6 * c – 6 / a) - b b. (5 * c) +( a* b / b) c. ++a d. c + a * c / (3 * c)

35. Exercise: 29 Arithmetic Expression Assume i,j and k are integer variables with i = 5 and j=3. Determine what is the value for each of the following statement: a) k = j++; d) k = ++j; b) k = i * j--; e) k = i * --j; c) k = j + i * j++; f) k = 27 / j++ - 16 % i;

36. 30 Relation Expression Relational expression use Relational operator Combination of more than one statement variable vs variable Can consists of variable vs constant produce constant vs constant 0 (if false) 1(if true)

37. Relational Operator 31 Relation Expression

38. 32 Relation Expression P/s: a, b and c are variables, Replace with the given values Example 1: int a=6, b =1, c = -2; a+ b == c 2) a != b 6 + 1== -2 6 != 1 7 == -2 Answer: 0(False) Answer : 1 (True)

39. 33 Relation Expression Example 2 : int a=6, b =1, c = -2; 3) b < a 4) b + c <= a 1 < -2 1 + -2 < 6 -1 < 6 Answer: 0 (False) Answer : 1 (True)

40. 34 Relation Expression P/s: Relational operator has less priority than other operators. Start evaluating from left to right. Example 3: int a=10, b = 3, c = 7; (a+b >= 3*c)==( a != 2*c+b) (10+3 >= 3*7)==(a != 2*c+b) (13 >= 21)==(10 != 14+3) (13 >= 21)==(10 != 17) 0 == 1 0 (false)

41. 35 Relation Expression An example program which uses relational expression #include <stdio.h> void main() { int age; printf(“Please enter your age >>”); scanf(“%d”,&age); if (age > 21) printf(“You are qualified to vote”); } Relational expression

42. 36 Logical Expression Logical Operator Logical expression use Combination of one or more expressions Can consists of Relational expr. vs logical expr. Relational expr. vs variable produces Relational expr. vs constant 0 (if false) 1(if true)

43. 37 Logical Expression Logical Operator Logical operator && dan || is used between 2 or more relational expression

44. 38 Logical Expression Logical operator truth table for AND AND (&&)

45. 39 Logical Expression Logical operator truth table for OR OR (||)

46. 40 Logical Expression Logical operator truth table for NOT NOT(!)

47. 41 Logical Expression Example 1: Evaluate the following logical expression: (2 < 5 ) && ( 5 < 10) b) (7 % 2 < 2) || ( 2 * 3 == 6) 1 && 1 (1 < 2) || (6 == 6) 1 1 || 1 1

48. 42 Logical Expression Example 2: Evaluate the following logical expression: Given a = 3, b = 4; c) !((5 * b <= 23 - a )) d) ! ((b +3 != 8) &&( 3 * a < 2)) !((5 * 4 <= 23 – 3)) !(( 7 != 8 ) && ( 9 < 2 )) !(20 <= 20) ! ( 1 && 0 ) !(1) ! ( 0) 0 1

49. 43 Logical Expression Logical Expression An example program which using Logical Expression: #include <stdio.h> void main() { int mark; printf(“Enter your mark >>”); scanf(“%d”,&mark); if (mark >= 85 && mark <= 100) printf(“Gred A”); else if( mark >=80 && mark <=84) printf(“Gred A-”); }

50. Exercise: 44 Logical Expression Given with i=2, j = 5 and k = 15. Evaluate each of the following expression: a) i > j – k g) k == j + I * j b) i != k h) k <=k /j c) (i >= 1) && (j == 5) i) (j < i) || (k > j) d) !( i > j) j) (i >0) && (j <k) || (k <i) e) i < j < k k) i * k < k / j f) (i < j) && (j < k) i) i – j > k Complete the following statements with suitable logical expression. int angka1,angka2; if (angka1 is less than or equal to angka2) printf(“%d is less than or equal to %d”,angka1,angka2);