Input a number #include using namespace std; int main() { int num; cout << "Enter a number" << endl; cin >> num; return 0; }

Print positive if greater than 0 #include using namespace std; int main() { int num; cout << "Enter a number" << endl; cin >> num; if (num >= 0) cout << "positive" << endl; return 0; } Enter 5 => positive Enter -5 => no output

Add ; #include using namespace std; int main() { int num; cout << "Enter a number" << endl; cin >> num; if (num >= 0); cout << "positive" << endl; return 0; }

Add ; #include using namespace std; int main() { int num; cout << "Enter a number" << endl; cin >> num; if (num >= 0); cout << "positive" << endl; return 0; } Enter 5 => positive Enter -5 => positive Why?

Add ; #include using namespace std; int main() { int num; cout << "Enter a number" << endl; cin >> num; if (num >= 0) ; cout << "positive" << endl; return 0; } Enter 5 => positive Enter -5 => positive Why? ; is null statement

Print if negative also

#include using namespace std; int main() { int num; cout << "Enter a number" << endl; cin >> num; if (num >= 0) cout << "positive" << endl; else cout << "negative" << endl; return 0; }

Print if negative also #include using namespace std; int main() { int num; cout << "Enter a number" << endl; cin >> num; if (num >= 0) cout << "positive" << endl; else cout << "negative" << endl; return 0; } Enter 5 => positive Enter -5 => negative

Input a number, print if even or odd #include using namespace std; int main() { int num; cout << "Enter a number" << endl; cin >> num; return 0; }

Input a number, print if even or odd #include using namespace std; int main() { int num; cout << "Enter a number" << endl; cin >> num; if (xxxx) cout >> "even" << endl; else cout <<"odd" << endl; return 0; }

Input a number, print if even or odd #include using namespace std; int main() { int num; cout << "Enter a number" << endl; cin >> num; if (num % 2 == 0) cout >> "even" << endl; else cout <<"odd" << endl; return 0; }

What is wrong with this solution? #include using namespace std; int main() { int num; cout << "Enter a number" << endl; cin >> num; if (num % 2 = 0) cout >> "even" << endl; else cout <<"odd" << endl; return 0; }

Watch = (assignment) vs == (test for equality) #include using namespace std; int main() { int num; cout << "Enter a number" << endl; cin >> num; if (num % 2 = 0) should be num %2 == 0 cout >> "even" << endl; else cout <<"odd" << endl; return 0; }

Selection exercises 1.Input an age and print “over the hill” if over Input an age and print whether the individual is legal to drink or underage 3. Change the above problem to use a constant 4. Input a temperature and print whether it is freezing or above 5. Input 2 integer values, print out the largest.

constant 1.Declare a variable type name; 2. int LEGAL_AGE; //use caps for constants 3.const int LEGAL_AGE; //make it constant 4.const int LEGAL_AGE = 21; //give it a value

Selection exercises 1.Input an age and print “over the hill” if over 40 #include using namespace std; int main() { int age; cout << "Enter an age" << endl; cin >> age; if (age >= 40) cout << "Over the Hill" << endl; return 0; }

2. Input an age and print whether the individual is legal to drink or underage #include using namespace std; int main() { int age; cout << "Enter an age" << endl; cin >> age; if (age >= 21) cout << "Legal to drink" << endl; else cout << "Underage" << endl; return 0; }

3. Change the above problem to use a constant #include using namespace std; int main() { int age; const int LEGAL_AGE = 21; cout << "Enter an age" << endl; cin >> age; if (age >= LEGAL_AGE) cout << "Legal to drink" << endl; else cout << "Underage" << endl; return 0; }

//4. Input a temperature and print whether it is freezing or above #include using namespace std; int main() { float temp; const float FREEZING = 32; cout << "Enter a temperature" << endl; cin >> temp; if (temp <= FREEZING) cout << "Freezing" << endl; else cout << "Above Freezing" << endl; return 0; }

//5. Input 2 integer values, print out the largest. #include using namespace std; int main() { int num1; int num2; cout << "Enter two numbers" << endl; cin >> num1 >> num2; if (num1 > num2) cout << num1 << " is largest" << endl; else cout << num2 << " is largest" << endl; return 0; }

//5. Input 2 integer values, print out the largest. #include using namespace std; int main() { int num1; int num2; cout << "Enter two numbers" << endl; cin >> num1 >> num2; if (num1 > num2) cout << num1 << " is largest" << endl; else cout << num2 << " is largest" << endl; return 0; } Enter 5 and 3 => 5 is largest Enter 3 and 5 => 5 is largest Enter 3 and 3 => 3 is largest

What if they are equal?

//5. Input 2 integer values, print out the largest. #include using namespace std; int main() { int num1; int num2; cout << "Enter two numbers" << endl; cin >> num1 >> num2; if (num1 > num2) cout << num1 << " is largest" << endl; else if (num2 < num1) cout << num2 << " is largest" << endl; else cout << "same" << endl; return 0; }

This is better, remove whitespace //5. Input 2 integer values, print out the largest. #include using namespace std; int main() { int num1; int num2; cout << "Enter two numbers" << endl; cin >> num1 >> num2; if (num1 > num2) cout << num1 << " is largest" << endl; else if (num2 < num1) cout << num2 << " is largest" << endl; else cout << "same" << endl; return 0; }

//input a number, print if positive, negative, or zero #include using namespace std; int main() { int num; cout << "Enter a number" << endl; cin >> num; if (num > 0) cout << "positive" << endl; else if (num < 0) cout << "negative" << endl; else cout << "zero" << endl; return 0; }

Better if (num > 0) cout << "positive"; else if (num < 0) cout << "negative"; else cout << "zero"; Less efficient, why? if (num > 0) cout << "positive"; if (num < 0) cout << "negative"; if (num == 0) cout << "zero";

Calculate pay What if your work overtime? Time and a half for overtime Overtime is over 40 hours Double overtime is over 60 hours

Hint Calculate regular pay first

//calculate regular pay first #include using namespace std; int main() { float payRate; float hrsWorked; float totalPay; cout << "enter hours worked" << endl; cin >> hrsWorked; cout << "enter pay rate" << endl; cin >>payRate; if (hrsWorked <= 40) { totalPay = hrsWorked * payRate; cout << "totalpay is " << totalPay << endl; } return 0; }

Next hint:Add variables regPay, otPay Next calculation is hours less than 60, regular overtime

float payRate; float hrsWorked; float totalPay; float regPay; float otPay; cout << "enter hours worked" << endl; cin >> hrsWorked; cout << "enter pay rate" << endl; cin >>payRate; if (hrsWorked <= 40) { totalPay = hrsWorked * payRate; cout << "totalpay is " << totalPay << endl; } else if (hrsWorked <= 60) { regPay = ?? otPay = ?? totPay = ?? cout << ??? }

float payRate; float hrsWorked; float totalPay; float regPay; float otPay; cout << "enter hours worked" << endl; cin >> hrsWorked; cout << "enter pay rate" << endl; cin >>payRate; if (hrsWorked <= 40) { totalPay = hrsWorked * payRate; cout << "totalpay is " << totalPay << endl; } else if (hrsWorked <= 60) { regPay = 40 * payRate; // regular pay otPay = (hrsWorked – 40) * payRate; // overtime pay totPay = ?? cout << ??? }

float payRate; float hrsWorked; float totalPay; float regPay; float otPay; cout << "enter hours worked" << endl; cin >> hrsWorked; cout << "enter pay rate" << endl; cin >>payRate; if (hrsWorked <= 40) { totalPay = hrsWorked * payRate; cout << "totalpay is " << totalPay << endl; } else if (hrsWorked <= 60) { regPay = 40 * payRate; // regular pay otPay = (hrsWorked – 40) * payRate; // overtime pay totPay = regPay + otPay; cout << ??? }