آبان 85 (C) NematAllah Ahmadyan 1

Flowchart & Control Structures

Introduction to Programming course

40-143c

آبان 85 (C) NematAllah Ahmadyan 2

At a glance

Control Structures Control Statements

• If

• for

• while

• Switch

• do…while

• …

آبان 85 (C) NematAllah Ahmadyan 3

IF and IF…ELSE structure

1. int x = … ;2. if ( x%3 == 0 ){ 3. … /* x = 3k */4. }else if ( x%3 ==

1 ){ 5. … /* x = 3k + 1 */6. }else {7. … /* x = 3k +2 */8. }

آبان 85 (C) NematAllah Ahmadyan 4

FOR structure

1. int i , j;2. for (i=1 ; i<=size-1 ; i++)

{3. for(j=1 ; j<size-1 ; j++){4. if(a[j] > a[j+1])5. swap(&a[j],&a[j+1]);6. }7. }8. /* this is a main code of

bubble-sort */

آبان 85 (C) NematAllah Ahmadyan 5

WHILE & DO…WHILE structure

1. int input = 0;2. int sum = 0 ;3. while ( input!=-1 )

{4. scanf(“%d”,

&input );5. sum += input ;6. }

آبان 85 (C) NematAllah Ahmadyan 6

WHILE & DO…WHILE structure

1. int number, digit, number_r ;

2. do {3. digit = number % 10 ;4. number /= 10 ;5. number_r += digit *

pow(10,num_digit-i);

6. ++i ;7. }while(number >

0);

آبان 85 (C) NematAllah Ahmadyan 7

BREAK structure1. for ( i = 3 ; ; i += 2 ) {2. term =3. _sign * (pow(x,i) / fact(i)) ;4. _sign = -1 * _sign ;5. abs = term>0 ? term :

-term ;6. if ( abs < 0.0001 )

break;7. sine = sine + term ;8. }9. /* calculate sin(x) from 10. x - x^3 / 3! + x^5/5! ... */11. /* while(1){} can be used

too. */

آبان 85 (C) NematAllah Ahmadyan 8

SWITCH structure

1. switch(j){2. case 0: k=1; break;3. case 1: k=2; break;4. case 2: k=0; break;5. default: {6. printf(“ERROR");7. exit(1);8. }9. }

آبان 85 (C) NematAllah Ahmadyan 9

Finally…

CommentingClear code Versus Tricky codeAvoid labels: and goto