Start

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Start
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More Loops

• 03/14/11
• Look at geometric series example.

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Other Loops

• for-loop and do-while

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for - loop

• Can use while-loop for all repetition
• for is useful for counting

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Example

• //Add first ten integers
• int total 0
• for (int n 1 n lt 10 n)?
• total total n
• cout ltlt total
• OUTPUT
• 55

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Syntax of for

• for(intialization repetition cond update)
  statement
• for(intialization repetition cond update)
• //Code of for-loop block
• Initialization done upon entry.
• Condition must be true, check each time.
• Update done after each iteration, before
  condition is checked.

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while vs. for

• int total 0
• for (int n 1 n lt 10 n)?
• total total n

• total 0
• int n1
• while (n lt 10)?
• total total n
• n

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Other Examples

• Input the rainfall for the week
• forrain.cpp
• To find a Fibonacci number.
• fib.cpp

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Output Geometric Series

• A geometric series is defined by
• a ar ar2 ar3 ... arn-1
• a is first term, r is common ratio, and n is
  number of terms. Write a function to take a, r
  and n then return the sum.
• Start with an algorithm

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Algorithm

• Parameters a, r, n
• term a (1st term is a)
• sum term
• for(i from 2 to n)
• Find ith term, termr
• Add term to sum
• Output sum

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Geometric Series Program

• geometric.cpp
• Program started.
• Let's provide the function, using a for-loop.

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Do-while loop

• do
• stmts
• while (bool. expr.)?
• Executed Once
• Then condition check

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dowhile

• dowhile.cpp

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What is needed?

• Finish for loop in countdown.cpp