Lecture 5 repetition statements

Statements 11 Given N, the number of the first natural numbers greater than 0, calculate and print the total sum of these N first natural numbers... Statements 17 Given N, the number

Chapter 5: Repetition Statements

chauvtn@hcmut.edu.vn)

References

 [1] “C: How to Program”, 7th Ed – Paul

Deitel and Harvey Deitel, Prentice Hall, 2012

– Brian W Kernighan and Dennis M Ritchie, Prentice Hall, 1988

 and others, especially those on the Internet

3

double minNumber = positiveNumber[0];

iteration = iteration + 1;

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

submit homework (i.e no attachment exists)

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

while Statements

11

Given N, the number of the first natural numbers

greater than 0, calculate and print the total sum of

these N first natural numbers

while Statements

Given N, a natural number greater than 0, calculate and print the

factorial of N: N! = 1*2* *N = (N-1)!*N

while Statements

13

Given a natural number N

greater than 0, list a series of

Fibonacci numbers smaller than N

<Statements> are always performed at least once!

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

do while Statements

17

Given N, the number of the first natural numbers

greater than 0, calculate and print the total sum of

these N first natural numbers

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

19

Given a sequence of N numbers input sequentially

by a user, find the minimum one

for Statements

1. <expression_1> is evaluated

2. <expression_2> is evaluated

3. If <expression_2> is true (0), <Statements> are performed,

<expression_3> is evaluated, and then go to step 2 Otherwise, i.e

if <expression_2> is false (=0), go to step 4

4. End the repetition statement and move forward 21

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

for Statements

25

Given N, a natural number greater than 0, calculate and print the

factorial of N: N! = 1*2* *N = (N-1)!*N

for Statements

Given a natural number N greater than 0, list all the squared numbers

smaller than the given number

for Statements

27

while (<expression_1>) {

…

do {

… }

while (<expression_2>);

…

for(<expression_3>;<expression_4>;<expression_5>) {

… }

… }

for (…; …; …) {

…

for (…; …; …) {

… }

Nested Repetition Statements

29

Given a size of a window (N is an odd number and N>=5),

print a star of stars: diagonal and center lines

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

Nested Repetition Statements

31

N=5

Given a natural number greater than 0, print two squared isosceles triangles of stars

continue Statements

remainder of the body of a repetition

statement and proceeding with the next

iteration of the loop

 while statements

 do while statements

continue Statements

The second loop has been skipped!

break Statements

from certain control statements

 switch case statements

 while statements

 do while statements

 for statements

Infinite Loops

37

Put them all together

Natural number e is approximated:

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

Put them all together

39

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

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:

41

N=10

N=9

How to start the spiral at

any given position (i,j)?

 Repeat actions in connection with conditions

 Important and helpful for controlling the loops in repetition

Chapter 5: Repetition Statements