Objective:

1. Objective: Students will be able to: Declare and use variables Input integers

2. Variables • Hold data • Can be numbers, letters, words • Place in main memory that holds the data • Has a name that is assigned by the programmer

3. Example • intalice; Type: int integer (whole number) alice: name of variable Variable is declared. ;

4. program to input an integer and have it print out (echo) #include <iostream> using namespace std; int main (void) { intalice; cin >>alice; cout<< “There is an echo “; cout << alice; cin.get(); return0; }

5. Variable Names • Can consist of numbers, letters, and underlines • Can be as long as you like Provided that: • It starts with a letter • It is unique for that program somewhere in the first 32 characters • Doug and doug are different • Can’t be a keyword

6. Examples of variable names • count • Sum • Salary, • Next_character • total • reply

7. Type in and run the cin program. Make sure to type a number in when you run the program • What were the results:

8. Assignment • One way to assign a value to a variable is to input a number from the keyboard like we just did in the last program. • Another way is to use an assignment statement: • intalice, bill; declares variables • cin>>alice input number for alice • bill = alice; makes bill equal to alice • cout<< bill; prints out number inputted

9. Self Test: What do these lines of code do? • int Alice, Tom; • cin >> Alice >> Tom; • Alice = Tom; • Tom = Alice; • cout << Alice << Tom;

10. Answer goes here!

11. Self Test: What do these lines of code do? • int Alice, Tom, Save; • cin >> Alice >>Tom; • Save = Alice; • Alice = Tom; • Tom = Save: • cout<< Alice << Tom;

12. Answer goes here!