COSC175-Selection1 Decisions Given hours worked and pay rate, calculate total pay What if you work overtime? How do you indicate if your work overtime? How about double overtime?

COSC175-Selection2 Relational Operators < less than <= less than or equal to > greater than >= greater than or equal to == equals != not equal to

Examples COSC175-Selection > 2 2.'a' < 'c' Why is this true? 3.x != y 4.temp > humidity 5.num == 35 6.initial != ‘Q’

COSC175-Selection4 Logicals: AND && OR || NOT !

COSC175-Selection5 Examples 1. if ((sex == 'F') && (city_code == 18) && (gpa >= 3.7)) cout << "Merit Award" << endl; 2. if ((zip == "48002") || (zip == "48003") || (zip == "48004")) cout << "LOCAL“ << endl;

“Short-Circuit” Evaluation Process in which the computer evaluates a logical expression from left to right and stops as soon as the value of the expression is known one True in || -> True one False in && -> False Example: int age; int height; age = 25; height = 70; 1.((age > 50) && (height > 60)) 2. ((height > 60) || (age > 40))

COSC175-Selection7 Selection/Decision Test – true or false One operation performed if true One operation performed if false Keywords –if, else

COSC175-Selection8 if ( Expression ) statement NOTE: statement can be a single statement, a null statement, or a compound statement. if Syntax

COSC175-Selection9 if statement is a selection of whether or not to execute a statement (which can be a single statement or an entire block ) TRUE FALSE statement expression

COSC175-Selection10 Examples 1.if (taxCode == ‘ T’ ) price = price + taxRate*Price; 2. if (num < 0 ) { // compound statement cout << "Negative" << endl; numNegs = numNegs + 1; } 3. if (age < 21 ) cout << "Under Age"

COSC175-Selection11 if ( Expression ) StatementA else StatementB NOTE: StatementA and StatementB each can be a single statement a null statement, or a compound statement. if-else Syntax

COSC175-Selection12 if..else provides two-way selection between executing one of 2 clauses (the if clause or the else clause) TRUE FALSE if clauseelse clause expression

COSC175-Selection13 int carDoors, driverAge; float premium, monthlyPayment;... if ( (carDoors == 4 ) && (driverAge > 24) ) { premium = cout << "LOW RISK “ << endl; } else { premium = cout << “ HIGH RISK ” << endl; } monthlyPayment = premium / ;

COSC175-Selection14 Example InputProcessOutput tempInput temp, unitsnewTemp unitsConvert temperature Output newTemp Convert temperature from fahrenheit to celsius or from celsius to fahrenheit based on C or F

COSC175-Selection15 code int main() { float temp; float newTemp; char units; cout << " Enter temperature and C or F" cin >> temp >> units; if (units == 'F') { newTemp = (5 * (temp – 32) )/9; cout << temp<< "Degrees F = " <<newTemp<<" Degrees C“; } else { newTemp = ((9 * temp)/5) + 32; cout << "Degrees C = " << newTemp << " Degrees F“ << endl; } } // end main

COSC175-Selection16 Exercises: 1.Write the statements that allow you to input a number and prints whether it is positive or negative. 2.Write the statements necessary to input the price of apples and the price of oranges. Then print either "THE APPLES COST MORE" or "THE ORANGES COST MORE. How would you handle the situation where the cost was the same? 3.Write the statements that allow you to input a number and prints whether it is odd or even.

COSC175-Selection17 Nested selection - Example if (hrsWorked <= 40 ) totPay = hrsWorked * payRate; else { regPay = 40 * payRate; if (hrsWorked <= 60) { otPay = (hrsWorked – 40) * (1.5 * payRate); totPay = regPay + otPay; } else { otPay = 20 * (1.5 * payRate); doubleOtPay = (hrsWorked – 60) * (2 * payRate); grossPay = regPay + otPay + doubleOtPay; }

COSC175-Selection18 Writing a nested if statement as a Multiple-Alternative Decision if (x > 0) cout << “Positive” << endl; else if (x < 0) cout << “Negative” << endl; else cout << “Zero” << endl; if (x > 0) cout << “Positive” << endl; else if (x < 0) cout << “Negative” << endl; else cout << “Zero” << endl;

COSC175-Selection19 cin >> testGrade if (testGrade >= 90) letterGrade = ‘A‘; else if (testGrade >= 80) && testGrade < 90 letterGrade = 'B‘; else if (testGrade >= 70) && testGrade < 80 letterGrade = 'C‘; else if (testGrade >= 60) && testGrade < 70 letterGrade = 'D‘; else if testGrade < 60 letterGrade = 'F‘; Why is italicized code not necessary?

COSC175-Selection20 cin >> testGrade if (testGrade >= 90) letterGrade = 'A‘; else if (testGrade >= 80 ) letterGrade = 'B‘; else if (testGrade >= 70 ) letterGrade = 'C‘; else if (testGrade >= 60 ) letterGrade = 'D‘; else letterGrade = 'F‘;

COSC175-Selection21 if ( Expression1 ) Statement1 else if ( Expression2 ) Statement2. else if ( ExpressionN ) StatementN else Statement N+1 EXACTLY 1 of these statements will be executed. Nested if Statements

COSC175-Selection22 if ( creditsEarned >= 90 ) cout << “SENIOR STATUS “; else if ( creditsEarned >= 60 ) cout << “JUNIOR STATUS “; else if ( creditsEarned >= 30 ) cout << “SOPHOMORE STATUS “; else cout << “FRESHMAN STATUS “; Multi-way Branching

COSC175-Selection23 Use nested logic rather than straight thru logic if (age < 16) charge = 7; if ((age >= 16) && (age < 65)) charge = 10; if (age >= 65) charge = 5; if (age < 16 ) charge = 7; else if ((age >= 16) && (age < 65)) charge = 10; else if (age >= 65 ) charge = 5;

COSC175-Selection24 Testing Selection Control Structures to test a program with branches, use enough data sets so that every branch is executed at least once this is called minimum complete coverage

COSC175-Selection25 switch Use for multiple tests of one variable switch (selector) { case label1: statement 1 case label2: statement 2.. case label n: statement n default: statement e }

COSC175-Selection26 Example cin >> menuOpt; switch (menuOpt) { case 1: cout << "Beginners“; break; case 2: cout << "Advanced Beginner“; break; case 3: cout << "Intermediate“; break; default: cout << "Invalid Option“ } //END CASE

COSC175-Selection27 Example cin >> menuOpt; switch (menuOpt) { case 1: case 2: cout << “Buckle my shoe“; break; case 3: case 4: cout << “Shut the door“; break; case 5: case 6: cout << “Pick up stickse“; break; default: cout << "Invalid Option“ } //END CASE