Select Structures PDF

Select Structures  Outline Introduction Representing conditions : relational operators, logical expressions if statements switch - case statement 11/1/2024 Introduction to Programming  Introduction Practical progr...

Select Structures  Outline Introduction Representing conditions : relational operators, logical expressions if statements switch - case statement 11/1/2024 Introduction to Programming  Introduction Practical programs should always be implemented to allow a user to make a selection/Decision among available items/options/functionality. Eg – Male or Female – Single or Married – Age greater than 18 or Less than 18 – Single Player or Multiplayer This option/functionality is usually a condition that must be evaluated to either True or False. Each selection implements different instructions from the other 11/1/2024 Introduction to Programming  Example Write an algorithm to find the smallest number between two numbers entered by a user and display the results. In pseudocode form we get if condition is true Then do task A else (condition is false) Do Task-B endif 11/1/2024 Introduction to Programming  Pseudocode and Flowchart to find the smallest of two numbers (Selection/Decision/Branching) 11/1/2024 Introduction to Programming  Logical expressions and the relational operators In C++, a condition is represented by a logical expression /Boolean expression – has a value of either true or false. Suppose i and j are integers. Consider the expression: i > j 11/1/2024 Introduction to Programming Comparison Operators  Manipulating and Combining Logical expressions Logical /Boolean operators enable you to combine logical expressions. C++ has three logical /Boolean operators 11/1/2024 Introduction to Programming  If and switch Statements In C++, there are two selections, or branch control structures: – if statements – variations - if, if..else, if-else if, Nested if – switch structure. 11/1/2024 Introduction to Programming  if statement if- One way selection if.. else – Two way selection extended if /if..else..if – multiple selections Nested if 11/1/2024 Introduction to Programming Syntax  IF – One way Selection 11/1/2024 Introduction to Programming  If…else – Two Way Selection 11/1/2024 Introduction to Programming  Extended If – Multiple Selections 11/1/2024 Introduction to Programming  Nested if 11/1/2024 Introduction to Programming If statement example  Switch selection Structure C++’s switch structure gives the computer the power to choose from among many alternatives. Unlike the IF selection structure, the switch structure does not necessarily require a logical expression to be passed directly in the switch body. 11/1/2024 Introduction to Programming Switch statement example  break The break statement may or may not appear after each statement. The break statement, when executed in a switch structure, provides an immediate exit from the switch structure. 11/1/2024 Introduction to Programming Any Questions?