1. C Program Control Angela Chih-Wei Tang ( 唐 之 瑋 ) Department of Communication Engineering National Central University JhongLi, Taiwan 2010 Fall

2. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 2 Outline The for repetition statement switch multiple selection statement break and continue statements Logical operators Structured-programming summary

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4. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 4 The for Repetition Statement (1/3)

5. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 5 The for Repetition Statement (2/3) for loops can usually be rewritten as while loops: initialization; while ( loopContinuationTest ) { statement; increment; } Initialization and increment  example: for (int i = 0, j = 0 ; j + i <= 10 ; j++, i++) printf( "%d\n", j + i );

6. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 6 The for Repetition Statement (3/3) Initialization, loop-continuation, and increment can contain arithmetic expressions  example : if x equals 2 and y equals 10 for ( j = x; j <= 4 * x * y; j += y / x ) is equivalent to for ( j = 2; j <= 80; j += 5 ) "Increment" may be negative (decrement) If the loop continuation condition is initially false  the body of the for statement is not performed

7. Sum is 2550 Test 7C.E., NCU, Taiwan7 Angela Chih-Wei Tang, 2010

8. fig04_06.c (Part 1 of 2) 8C.E., NCU, Taiwan8 Angela Chih-Wei Tang, 2010

9. Year Amount on deposit 1 1050.00 2 1102.50 3 1157.63 4 1215.51 5 1276.28 6 1340.10 7 1407.10 8 1477.46 9 1551.33 10 1628.89 Test 9

10. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 10 Outline The for repetition statement switch multiple selection statement break and continue statements Logical operators Structured-programming summary

11. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 11 The switch Multiple-Selection Statement Useful when a variable or expression is tested for all the values Format  switch ( value ){ case '1': actions case '2': actions default : actions }  break ; exits from statement

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15. Enter the letter grades. Enter the EOF character to end input. a b c C A d f C E Incorrect letter grade entered. Enter a new grade. D A b ^Z Totals for each letter grade are: A: 3 B: 2 C: 3 D: 2 F: 1 Test 15

16. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 16 Outline The for repetition statement switch multiple selection statement break and continue statements Logical operators Structured-programming summary

17. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 17 The break and continue Statements – break Causes immediate exit from  while  for  do … while  switch Program execution continues with the first statement after the structure Common uses of the break statement  escape early from a loop  skip the remainder of a switch statement

18. 1 2 3 4 Broke out of loop at x == 5 Test 18

19. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 19 The break and continue Statements – continue Skips the remaining statements in the body of  while  for  do … while Proceeds with the next iteration of the loop

20. 1 2 3 4 6 7 8 9 10 Used continue to skip printing the value 5 Test 20

21. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 21 Outline The for repetition statement switch multiple selection statement break and continue statements Logical operators Structured-programming summary

22. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 22 Logical Operators

23. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 23 Operator Precedence and Associativity

24. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 24 Confusing Equality ( == ) and Assignment ( = ) Operators Dangerous error  nonzero : true  0 : false  example using == if ( payCode == 4 ) printf( "You get a bonus!\n" ); checks payCode, if it is 4 then a bonus is awarded  example using = if ( payCode = 4 ) printf( "You get a bonus!\n" ); sets payCode to 4 4 is nonzero, so expression is true  Logic error, not a syntax error

25. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 25 Outline The for repetition statement switch multiple selection statement break and continue statements Logical operators Structured-programming summary

26. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 26 Structured-Programming Summary (1/5) T F if statement (single selection) TF if … else statement (double selection) T F switch statement (multiple selection) break T F T F... Selection

27. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 27 Structured-Programming Summary (2/5) Repetition T F do … while statement T F while statement T F for statement

28. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 28 Structured-Programming Summary (3/5)....... Rule 2 Rule 1 - Begin with the simplest flowchart Rule 2 - Any rectangle can be replaced by two rectangles in sequence

29. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 29 Structured-Programming Summary (4/5) Rule 3 Rule 3 - Replace any rectangle with a control structure

30. C.E., NCU, Taiwan Angela Chih-Wei Tang, 2010 30 Structured-Programming Summary (5/5)