Introduction to Computer Programming (C language) - Chapter 5: Repetition Statements - Võ Thị Ngọc Châu

Nội dung text: Introduction to Computer Programming (C language) - Chapter 5: Repetition Statements - Võ Thị Ngọc Châu

1. Ho Chi Minh City University of Technology Faculty of Computer Science and Engineering Chapter 5: Repetition Statements Introduction to Computer Programming (C language) TS. Võ Thị Ngọc Châu (chauvtn@cse.hcmut.edu.vn, chauvtn@hcmut.edu.vn) 2017 – 2018, Semester 2
2. Course Content C.1. Introduction to Computers and Programming C.2. C Program Structure and its Components C.3. Variables and Basic Data Types C.4. Selection Statements C.5. Repetition Statements C.6. Functions C.7. Arrays C.8. Pointers C.9. File Processing 2
3. References [1] “C: How to Program”, 7th Ed. – Paul Deitel and Harvey Deitel, Prentice Hall, 2012. [2] “The C Programming Language”, 2nd Ed. – Brian W. Kernighan and Dennis M. Ritchie, Prentice Hall, 1988 and others, especially those on the Internet 3
4. Content Introduction while Statements do while Statements for Statements Nested Repetition Statements continue Statements break Statements Summary 4
5. Introduction Control statements in C  Sequence Assignment Function calling  Selection if if else switch case  Repetition for while do while 5
6. Introduction Given a void main() { double positiveNumber[10] = {2, 1, 3, 10, 8, 3, 4, 5, 9, 12}; set of n int n = 10; positive double minNumber = positiveNumber[0]; int iteration = 1; numbers, while (iteration < n) { find the if (minNumber <= positiveNumber[iteration]) iteration = iteration + 1; smallest else { one. minNumber = positiveNumber[iteration]; iteration = iteration + 1; (Chapter 1 – } Real code in C) } Control Statements for Repetition } 6
7. Introduction A repetition statement allows you to specify that an action is to be repeated while some condition remains true. Example 1: Input validation  Ask a user to input a value  While his/her input value is invalid, ask him/her to input a value. Example 2: Search for any of you who didn’t submit homework (i.e. no attachment exists) Example 3: Count the number of occurrences of an important keyword in a text 7
8. while Statements while ( ) ; false (= 0) while ( ) { ; true ( 0) ; } 1. is evaluated. 2. If is true ( 0), are performed and then go to step 3. Otherwise, i.e. if is false (=0), go to step 4. 3. Go back to step 1. 4. End the repetition statement and move forward. 8
9. while Statements false (= 0) i =3 true ( 0) printf( ); i++; 9
10. while Statements Write a program to receive a natural number from a user. If an invalid value is entered, ask the user to input again until a valid one is obtained. 10
11. while Statements Given N, the number of the first natural numbers greater than 0, calculate and print the total sum of these N first natural numbers. 11
12. while Statements Given N, a natural number greater than 0, calculate and print the factorial of N: N! = 1*2* *N = (N-1)!*N 12
13. Given a natural number N while Statementsgreater than 0, list a series of Fibonacci numbers smaller than N. 13
14. do while Statements do { ; ; true( 0) } while ( ); false(=0) are always 1. are performed. performed at least once! 2. is evaluated. 3. If is true ( 0), go to step 1. Otherwise, i.e. if is false (=0), go to step 4. 4. End the repetition statement and move forward. 14
15. do while Statements printf( ); i++; true( 0) i =3 false(=0)
16. do while Statements Write a program to receive a natural number from a user. If an invalid value is entered, ask the user to input again until a valid one is obtained. 16
17. do while Statements Given N, the number of the first natural numbers greater than 0, calculate and print the total sum of these N first natural numbers. 17
18. do while Statements Given N, a natural number greater than 0, calculate and print the factorial of N: N! = 1*2* *N = (N-1)!*N 18
19. Given a sequence of N numbers input sequentially by a user, find the minimum one. 19
20. for Statements false (=0) true ( 0) for ( ; ; ) ; for ( ; ; ) { ; ; } 20
21. for Statements false (=0) true ( 0) 1. is evaluated. 2. is evaluated. 3. If is true ( 0), are performed, is evaluated, and then go to step 2. Otherwise, i.e. if is false (=0), go to step 4. 4. End the repetition statement and move forward. 21
22. for Statements for ( ; ; ) ; is regarded as: ; while ( ) { ; ; } for ( ; ; ) { ; ; } is regarded as: ; while ( ) { ; ; ; } 22
23. for Statements i=1; false (=0) i =3”. 23
24. for Statements Given N, the number of the first natural numbers greater than 0, calculate and print the total sum of these N first natural numbers. 24
25. for Statements Given N, a natural number greater than 0, calculate and print the factorial of N: N! = 1*2* *N = (N-1)!*N 25
26. for Statements Given a natural number N greater than 0, list all the squared numbers smaller than the given number. 26
27. for Statements 27
28. while ( ) { Nested Repetition do { Statements } while ( ); for( ; ; ) { } } for ( ; ; ) { A repetition statement for ( ; ; ) { can contain other } while ( ) { repetition statements in } many various } combination ways. 28
29. Nested Repetition Statements Given a size of a window (N is an odd number and N>=5), print a star of stars: diagonal and center lines 29
30. Nested Repetition Statements Given a natural number N greater than 0, print a triangle full of stars. N is the height of the star triangle. N = 4 30
31. Given a natural number greater than 0, Nested Repetitionprint two Statements squared isosceles triangles of stars. N=5 31
32. continue Statements the continue statement for skipping the remainder of the body of a repetition statement and proceeding with the next iteration of the loop  while statements  do while statements  for statements 32
33. continue Statements The second loop has been skipped! 33
34. break Statements the break statement for exiting immediately from certain control statements  switch case statements  while statements  do while statements  for statements 34
35. break Statements All the loops from the second loop have been skipped! A corresponding repetition statement is then ended. 35
36. Infinite Loops while (1) ; do { ; while (1) { ; ; } ; while (1); } for ( ; 1; ) for (; ;) ; ; for (; ;) { ; for ( ; 1; ) { ; ; } ; } 36
37. Infinite Loops 37
38. Put them all together Write a program to compute an approximation of e with a positive number N input by a user. Print the approximated value and its difference from a commonly used value which is 2.71828. It is given that: 0! = 1! = 1. Natural number e is approximated: 38
39. Put them all together Write a program to compute an approximation of the power x of e where there is no use of a true value of e. Accuracy of an approximation is dependent on how large n is. 39
40. Put them all together Given problem: print the first NxN natural numbers greater than 0 in a spiral-shaped matrix with a given N. Given N = 4, a printed spiral-shaped matrix is as follows: 1 2 3 4 0 12 13 14 5 12 11 16 15 6 10 9 8 7 Given N = 5, a printed spiral-shaped matrix is as follows: 1 2 3 4 5 0 16 17 18 19 6 16 15 24 25 20 7 24 14 23 22 21 8 13 12 11 10 9 40
41. N=10 N=9 How to start the spiral at any given position (i,j)? 41
42. Summary Three control statement types of repetition  while  do while  for Repeat actions in connection with conditions break and continue statements  Important and helpful for controlling the loops in repetition Infinite loops  Check the conditions for repetition carefully 42
43. Chapter 5: Repetition Statements 43