REACH TEST REVIEW

1. CECS 121 EXAM 1 REACH TEST REVIEW

2. Parts of the Program /* C Programming for the Absolute Beginner */ // by Michael Vine #include <stdio.h> #include <stdlib.h> main() { printf(“\nC you later\n”); system(“pause”); }

4. Program Statements Serve to control program execution and functionality. Must end with a semicolon(;) with the exception of: • Comments: /* */ • Preprocessor Directives: #include or #define • Begin and end program identifiers: { } • Function definition beginnings: main()

5. The main{} function • Functions allow you to group program statements under one name • C is case-sensitive so main(), MAIN(), and Main() are all different • The main function is special because the values it returns are returned to the operating system • Most main functions in this course do not take or pass information to the operating system

6. Escape Sequences • Definition: Escape sequences are specially sequenced characters used to format output • \” • Ex: printf(“ \ “This is quoted text \ “ “) • \’ • Ex: printf(“ \n A single quote looks like \’ \n”); • \* *\ Comment Block

7. Directives • #include <stdio.h> • Using a directive to include a header file • stdio.h = standard input output header file • stdlib.h = ‘system’ commands

8. Memory • A computer’s long-term memory is called nonvolatile memory and is generally associated with mass storage devices, such as hard drives. • A computer’s short term memory is called volatile memory. It loses is data when power is removed from the computer

9. Data Types To declare a constant (read only) value: const int x = 20; const float PI = 3.14;

10. Variable Types

11. Printf() ; Scanf() • Can you explain what the code is doing?

12. Conversion Specifiers • Character - %c • Integer - %d • Float (decimal)- %f • String - %s • Printf Format Tags: %[flags][width][.precision][length]specifier %[.precision]specifer -> %.2f

13. Can you predict the printout? • int main() { printf (“%c %c \n", 'a', 65); printf (" %10d \n", 1977); printf ("%010d \n", 1977); printf ("floats: %4.2f \n", 3.1416); printf ("%s \n", "A string"); printf(“%f \n”, 55.55); return 0; } }

14. Printouts printf (“%c %c \n", 'a', 65); aA printf ("%d %ld\n", 1977, 650000L); 1977650000 printf (" %10d \n", 1977); 1977 printf ("%010d \n", 1977); 0000001977 printf ("floats: %4.2f \n", 3.1416); 3.14 printf ("%s \n", "A string"); A string • Can you create a tabular data using printf?

15. Review Printing with Precision

16. Scanf • Syntax scanf(“conversion specifier”, variable);

17. Can you predict the printout when the user enter 2 and 4? #include <stdio.h> main() { int iOperand1 = 0; int iOperand2 = 0; printf(“\n Enter first operand: “); scanf(“%d”, &iOperand1); printf(“\n Enter second operand: “); scanf(“%d”, &iOperand2); printf(“The result is %d \n”, 24/(iOperand1 * iOperand2)+6/3); }

18. Arithmetic and Order of Precedence

19. Can you predict the printout? #include <stdio.h> main() { int x = 4; int y = 9; int result1, result2; result1 = y/x; result2 = y%x; printf(“The result is %d.%d \n”, result1, 25*result2); }

20. Conditions and Operators

21. Boolean Operators Do you know the answers to these? • A. !( 1 || 0 ) • B. !( 1 || 1 && 0 ) • C. !( ( 1 || 0 ) && 0 )

22. Boolean Operators Quiz Answers • A. !( 1 || 0 ) ANSWER: 0 • B. !( 1 || 1 && 0 ) ANSWER: 0 (AND is evaluated before OR) • C. !( ( 1 || 0 ) && 0 ) ANSWER: 1 (Parenthesis are useful)

23. If Statements

24. Quiz • Can you write code that will ask a user to enter a number 1 , 2 , or 3 and print out the following:

25. Answer #include <stdio.h> int main() { int a; printf (“Enter one of the following: %d, %d, or %d\n”, 1, 2, 3); scanf(“%d”, &a); if(a==1|| a==2|| a ==3) { if(a==1){ printf(“\n %d is the loneliest number \n“, 1); } if(a==2){ printf(“\n%d is better than %d \n”,2,1); } if(a==3){ printf(“\n%d \’ s a crowd \n”,3); } else printf(“Sorry, you entered an invalid value\n”); return 0; }

26. Switch-Case Statments

27. Example Switch-Case Statement

28. Loops • while ( condition ) { Code to execute while the condition is true } • Quiz: Can you write a program that prints x while x increments from 0 to 10?

29. Answer While Quiz

30. Operators Cont. x++; Tells the function to use the current value of x and increment it by 1. ++x; Increment the value of x by 1 and use the new value for calculations. x--; Tells the function to use the current value of x and decrease its value by 1. --x; Decrease the value of x by 1 and use the new value for calculations. x=0; printf(“The Value of x is: %d”, x++); printf(“\n The Value of x is: %d”,++x); Would results in: The Value of x is: 0 The Value of x is: 2

31. For Loop • Often used when the # of iterations is already known. • Contains 3 separate expressions: • Variable initialization • Conditional expression • Increment/Decrement Try writing a program with a for loop that counts down from 10 seconds.

32. For Loop #include <stdio.h> main() { int x=0; for(x=10; x>=0; x--) { printf("%d \n", x); } system("pause"); }

33. Break/Continue Statements • break; Used to exit a loop. Once this statement is executed the program will execute the statement immediately following the end of the loop. • continue; Used to manipulate program flow in a loop. When executed, any remaining statements in the loop will be skipped and the next iteration of the loop will begin

34. Questions?