1. CS31 You Lu CS31-1K TA

2. Hello World!

3. Variable

4. Out of the Range You input 8888888888, but it outputs another different number.

5. I/O cin >> cout <<

6. Input one word or string cin>>s; //can only input one word, e.g., only my first name. getline(cin, s); //can input the whole string, e.g., my first and last name

7. cin.ignore(10000, '\n') Use cin.ignore(10000, '\n') after reading a number if the next input will be of a string (using getline)

8. Arithmatic Division: 5/2=2; 5.0/2=2.5 – as long as one of the number is a “double” we have a “double” division. Mod: 5%2=1 (remainder) Casting: – int a = 2.5 a = ? 2 – (double)5/2 = ? 2.5 – (double) (5/2) = ? 2

10. Visual Studio 2010 Check the output of compiler to see if there is any warning or error every time.

11. iostream precision Default is 6 digits If “double a = 1234.56789”; “cout << a” will only display 1234.57 Here you can use “cout.precision(9)” to set the output as 9 digits. See the example below.

12. iostream precision Be more careful to use “cout”

13. header file #include //standard built-in libraries #include “ccc_time.h” //user-defined libraries

14. if … if (condition) statement; condition: non-zero value means true; zero value means false;

15. another example

16. if…else… if (expression) statement; else statement; Nested if statement: if() { if() {…} else {…} } else if() { } else { }

17. Boolean expression Greater than or equal: “>=“ Less than or equal: “<=” Equal: “==” Not equal: “!=” Logic expression: – AND: && – OR: || – NOT: !

18. priority Arithmetic operator > relational operator 10 > 1+2 ↔ 10 > (1+2) “ logic operator cout << “true AND false is ” << (true && false);

19. priority highest! > >= < <= == != && lowest||

20. while loop while (expression) { statement; } do{ statement; } while (expression)

21. example

22. for loop for (initialization; condition; increment) { statement; } infinite loop: for(;;) { }

24. “continue” skip the current round loop, go to the next round loop for(…) { code 1; code 2; continue; code 3; }

25. example

26. “break” stop the current loop and get out of the loop. for (…) { code 1; code 2; break; code 3; } code 4

27. example

28. “goto” goto and “lable” must be in the same function. lable: goto [lable];

29. another example Jump out from a deep nested loop for(…) { for(…) { while(…) { if(…) goto stop; … } stop: cout << “Error in program. \n”; //”break” can only jump out from only one loop

30. Online reference Some websites are really helpful for you to learn C++, like http://www.cplusplus.com/http://www.cplusplus.com/ More detailed reference: Microsoft MSDN library – http://msdn.microsoft.com/en- us/vstudio/hh388567 http://msdn.microsoft.com/en- us/vstudio/hh388567 – http://msdn.microsoft.com/en- us/library/cscc687y(v=vs.80).aspx http://msdn.microsoft.com/en- us/library/cscc687y(v=vs.80).aspx – http://msdn.microsoft.com/en- us/library/3bstk3k5.aspx http://msdn.microsoft.com/en- us/library/3bstk3k5.aspx

31. Look up “rand()”

32. My webpage for CS31 1K http://www.cs.ucla.edu/~youlu/CS31-1K.html