OOP Chapter 5 : Program Looping

Object-Oriented Programming Language
Chapter 5 : Program Looping

Atit Patumvan
Faculty of Management and Information Sciences
Naresuan University

วันจันทร์ท่ี 27 กุมภาพันธ์ 12

2

Contents

• The for statement

• The while statement

• The do statement

• The break and continue Statements

Atit Patumvan, Faculty of Management and Information Sciences, Naresuan University Object-Oriented Programming Language


3

Triangular Number

n=4

sum = 1 + 2 + ... + n



4

Triangular Number Example

Program 5.1
01: #import <Foundation/Foundation.h>
02:
03:// Program to calculate the eighth triangular number
04:
05: int main(int argc, const char * argv[])
06:{
07:! NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
08:! int triangularNumber;
09:
10:! triangularNumber = 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8;
11:
12:! NSLog(@"The eighth triangular number is %i", triangularNumber);
13:
14:! [pool drain];
15:! return 0;
16:}

The eighth triangular number is 36



5

The for Statement

Program 5.2

02:
03:
05: {
07:! int n, triangularNumber;
08:
09:! triangularNumber = 0;
10:
11:! for(n = 1; n <= 200; n = n + 1)
12:! ! triangularNumber +=n;
13:
14:! NSLog(@"The 200th triangular number is %i", triangularNumber);
15:
16:! [pool drain];
17:! return 0;
18: }

The 200th triangular number is 20100



6

The for Statement

for( init_expression; loop_condition; loop_expression)
program_statement;
11:!for(n = 1; n <= 200; n = n + 1)
12:!! triangularNumber +=n;

1. The initial expression is evaluate ﬁrst.
2. The looping condition is evaluated.
3. The program statement is executed.
4.The looping expression is evaluated.
5. Return to step 2.


7

Table ot Triangular Number

Program 5.3
02:
03:
05: {
07:! int n, triangularNumber;
08:
09:! NSLog(@"TABLE OF TRIANGULAR NUMBERS");
10:! NSLog(@" n Sum from 1 to n");
11:! NSLog(@"-- ----------------"); for( init_expression; loop_condition; loop_expression)
12:
program_statement;
14:
TABLE OF TRIANGULAR NUMBERS
15:! for(n = 1; n <= 10; ++n){ n Sum from 1 to n
16:! ! triangularNumber +=n; -- ----------------
17:! ! NSLog(@" %i t%i", n, triangularNumber); 1 1
18:! } 2 3
3 6
19: 4 10
20:! NSLog(@"The 200th triangular number is %i", triangularNumber); 5 15
21: 6 21
7 28
22:! [pool drain]; 8 36
23:! return 0; 9 45
24: } 10 55
The 200th triangular number is 55



8

Keyboard Input

Program 5.4
02:
04: {
06:! int n, number, triangularNumber;
07:
08:! NSLog(@"What triangular number do you want?");
09:! scanf("%i", &number);
10:
12:
13:! for(n = 1; n <= number; ++n){
14:! ! triangularNumber +=n;
15:! }
16:
17:! NSLog(@"Triangular number %i is %in", number, triangularNumber);
18:
19:! [pool drain];
20:! return 0;
21: } What triangular number do you want?
22: 100
Triangular number 100 is 5050



9

Nested for Loops

Program 5.5
05:
05: {
05:! int n, number, triangularNumber, counter;
05:
05:! for(counter = 1; counter <= 5; ++counter){
05:! ! NSLog(@"What triangular number do you want?");
05:! ! scanf("%i", &number);
05:
05:! ! triangularNumber = 0;
05:
05:! ! for(n = 1; n <= number; ++n){
05:! ! ! triangularNumber +=n;
05:! ! }
05:
05:! ! NSLog(@"Triangular number %i is %i", number, triangularNumber);
05: ! }
05:! [pool drain];
05:! return 0;
05: }



10

The while Statement

while( expression )
program_statement

init_expression;
while( loop_condition )
{
program_statement;
loop_expression;
}



11

The while Statement

Program 5.6
02:
04: {
06:! int count = 1;
07:
08:! while( count <= 5){ init_expression;
09:! ! NSLog(@"%i", count); while( loop_condition )
10:! ! ++count;
11:! } {
12: program_statement;
13:! [pool drain]; loop_expression;
14:! return 0; }
15: }
16:!

1
2
3
4
5



12

Find the greatest common divisor

Program 5.7
02:
04: {
06:! unsigned int u, v, temp;
30 18
07:
08:! NSLog(@"Please type in two nonnegative integers.");
09:! scanf("%u%u", &u, &v);
10: 30 /18 = 1R12
11:! while( v != 0){
12:! ! temp = u % v; 18 /12 = 1R6
12 / 6 = 2R0
13:! ! u = v;
14:! ! v = temp;
15:! }
16:
17:! NSLog(@"Their greatest common advisor is %u", u);
18:
19:! [pool drain];
20:! return 0; Please type in two nonnegative integers.
21: } 30 18
22: Their greatest common advisor is 6
!



13

Program to reverse the digits of number

Program 5.8
01:
01:{
01:! int number, right_digit;
01:
01:! NSLog(@"Enter your number.");

1234 % 10 = 4
01:
01:! while( number != 0){
01:! ! right_digit = number % 10;
01:! ! NSLog(@"%i", right_digit);
1234 / 10 = 123
01:! ! number /= 10;
01:! }
01:
01:! [pool drain]; 123 % 10 = 3
01:! return 0;
01:} Enter your number.
123 /10 = 12
:
01: 1234
! 4
3
2
1



14

The do Statement

do
program_statement
while( expression )

init_expression;
do {
program_statement;
loop_expression;
} while( loop_condition )



15

Program to reverse the digits of number

Program 5.9
02:
04: {
06:! int number, right_digit;
07:
08:! NSLog(@"Enter your number.");
10:
11:! do{ init_expression;
12:! ! right_digit = number % 10; do{
13:! ! NSLog(@"%i", right_digit);
14:! ! number /= 10; program_statement;
15:! }while( number != 0); loop_expression;
16: } while( loop_condition );
17:! [pool drain];
18:! return 0;
19: }
01:!



16

The break and continue Statements

• Labeled break statement

• Exit from nested control structures

• Proceeds to end of speciﬁed labeled block

• Labeled continue statement

• Skips remaining statements in nested-loop body

• Proceeds to beginning of speciﬁed labeled block



OOP Chapter 5 : Program Looping

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