Simple%20Control%20Structures

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Simple Control Structures

• IF, IF-ELSE statements in C

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The if statement

• The if statement
• if (expression)
• statement
• How it works
• The expression is evaluated
• If the expression is TRUE the statement are
  executed and program continues to the next
  statement after IF
• If the expression is FALSE, program continues to
  the next statement after IF

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Flowchart for the if statement
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The if-else statement

• The if-else statement
• if (expression)
• statement1
• else
• statement2

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IF-ELSE works as follows

• Expression is evaluated
• If the expression is TRUE, statement1 is executed
  and program continues to the next statement after
  if-else
• If the expression is FALSE, statement2 is
  executes and program continues to the next
  statement after if-else

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Flowchart for the if-else statement
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SYNTAX ROOLES and INDENTATION

• If the statement in IF statement is a single
  statement, the curly braces could be omitted
• If the statement1 or/and statement2 is/are singe
  statements, the curly braces could be omitted
• INDENTATION
• The statement part of the if, if-else statement
  should be shifted

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EXAMPLES

• What would be the output of the following
  programming fragment?
• int a 10
• if (a gt 10)
• a a 1
• printf(d\n, a)
• a 0
• printf(d\n, a)

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EXAMPLES

• What would be the output of the following
  programming fragment?
• int a 9
• if (a gt 10)
• a a 1
• printf(d\n, a)
• a 0
• printf(d\n, a)

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EXAMPLES

• What would be the output of the following
  programming fragment?
• int a 10
• if (a gt 10)
• a a 1
• else
• a 0
• printf(d\n, a)