Topics to be covered

1
Topics to be covered

• Program Structure
• Constants
• Variables
• Assignment Statements
• Standard Output
• Standard Input
• Math Functions
• Character Functions
• System Limitations
• Algorithm Development
• Conditional Expressions
• Selection Statements
• Loop Structures

2
Structured Programming

• Structured Programming
• Combination of
• Sequences
• Selections
• Loops
• Sequences
• Series of operations that are performed in order.
• Selections
• Choose one path from two or more possible paths.
• Loops
• Execute a block of code repeatedly as long as
  some condition is met.

3
Basic Flowcharting Elements
Arrows show the flow - cannot diverge but can
converge.
Execution Block
Selection Block
Entry Point
Exit Point
Input/Output Block
4
Selection Statements

• Selectively choose one path of execution.
• Based on the evaluation of a test.
• Logical Test outcome is either TRUE or FALSE.
• FALSE if expression evaluates to ZERO.
• TRUE if expression evaluates to ANYTHING else.
• Three varieties of selection statements.
• if()/else
• switch()
• ()? (conditional or ternary operator)

5
Conditional Expressions

• (test)
• May be ANY expression that evaluates to a value.
• logical operator (!, , )
• relational operator (,!),(gt, lt), (lt,gt)
• assignment operator (equal to value assigned)
• single variable (or constant)
• function return value
• Test outcome is either TRUE or FALSE.
• FALSE if expression evaluates to ZERO - exactly.
• TRUE if expression evaluates to ANYTHING else.

6
if() and if()/else statements

• Syntax
• if(test)
• if_code
• else
• else_code

7
()? - conditional or ternary operator

• Syntax
• x (test)? if_exprelse_expr
• Shorthand version of if()/else

8
switch() statement

• Syntax
• switch(int_expr)
• case int_const1 code1
• break
• case int_const2 code2
• case int_const3 code3
• break
• default code4
• Compact way of writing certain types of complex
  but common if()/else blocks.

(int_expr) must evaluate to an integer value at
runtime. (int_constN) must evaluate to a unique
integer constant at compile time. execution
jumps to case where (int_constN int_expr) is
TRUE. break terminates switch()
execution. default case Optional. Executes only
if NO other case executes.
9
Loop Structures

• Special case of Selection Statement
• One branch eventually leads back to the original
  selection statement.
• Permits a block of code to be executed repeatedly
  as long as some test condition is satisfied.
• C provides three different looping structures
• while(), do/while(), for()
• Only one is needed and any one is sufficient.
• Different structures are better matches for
  different logic.
• Using the proper one aides the programmer and
  anyone else reading the code.
• The compiler doesnt care and will often
  implement the code identically regardless of
  which structure is used.

10
while() loop

• Syntax
• ini_code // not part of loop
• while(test_expr)
• loop_code
• increment_code
• next_code // not part of loop
• Features
• loop does not execute at all if test fails the
  first time.

11
do/while() loop

• Syntax
• ini_code // not part of loop
• do
• loop_code
• increment_code
• while(test_expr)
• next_code // not part of loop
• Features
• loop will always execute at least once, even if
  test fails the first time.

12
for() loop

• Syntax
• for(ini_code test_expr inc_code)
• loop_code
• next_code // not part of loop
• Features
• Just a while() loop with the initialization and
  increment code formally incorporated into the
  syntax.
• Can makes a cleaner divide between the loop logic
  and the housekeeping logic.
• Makes it harder to leave omit initialization code
  if loop is moved or copied.