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CS 1430: Programming in C++

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Input: 45.5 55 60.5 39.5 -1Input ends with -1Sentinel-Controlled Loop

Input: 4 45.5 55 60.5 39.5 Input begins with 4 (count)Count-Controlled Loop

Count-Controlled Loop

Input: 4 45.5 55 60.5 39.5

Variables totalCount: number of scores to processloopCount: number of iterations the loop body

has been executed (number of scores processed)

Pseudo CodeInput totalCount Set loopCount to 0 // LCVInitializing other variables While loopCount < totalCount Input the score Process score Increase loopCount by 1

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How to Initialize?

Range is known

const float MIN_SCORE = 0.0;

const float MAX_SCORE = 60.0;

// Initialize max

max = MIN_SCORE;

// Initialize min

min = MAX_SCORE;

// Initialize total

total = 0;

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Range is NOT known

// Input the first score

cin >> score;

// Initialize max

max = score;

// Initialize min

min = score;

// Initialize total

total = score;

// The range is knownconst float MIN_SCORE = 0.0; const float MAX_SCORE = 60.0;

float score, max = MIN_SCORE; int totalCount, loopCount;

// Interactive modecout << "Enter the count of scores: ";cin >> totalCount;

loopCount = 0; // No prime read of score!while (loopCount < totalCount) { // Interactive mode cout << "Enter a score: "; cin >> score; if (score < MIN_SCORE || score > MAX_SCORE) cout << "Invalid score: " << score; else { if (score > max) max = score; }

loopCount ++; } // Four Parts of Loop

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// Another way: No loopCount

float score, max = MIN_SCORE;int totalCount;

// Batch mode: no input prompt// cout << "Enter the count of scores: ";cin >> totalCount;

while (totalCount > 0) { // Batch mode: no input prompt // cout << "Enter a score: "; cin >> score; if (score < MIN_SCORE || score > MAX_SCORE) cout << "Invalid score: " << score; else { if (score > max) max = score; }

totalCount --; // totalCount = totalCount - 1;}

// What’s the value of totalCount after the loop?

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// The range is NOT known

float score, max; int totalCount, loopCount;

// Batch modecin >> totalCount; loopCount = 0;

while (loopCount < totalCount) { // Batch mode cin >> score;

if (loopCount == 0) // first score max = score; else { if (score > max) max = score; }

loopCount ++; }

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Average and Max of n ScoresRange is known

Invalid scores are not considered

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Initialize (total, max, validCount)Input totalCountWhile totalCount > 0 Input a score If score out of range display a message Else Increase validCount by one add score to total if score > max max = score

Decrease totalCount by one

// Average and Max of n Scores// Range is known and invalid scores are not considered

float score, max = MIN_SCORE, total = 0.0, average;int totalCount, validCount = 0;

cin >> totalCount;while (totalCount > 0){ cin >> score;

if (score < MIN_SCORE || score > MAX_SCORE) cout << "Invalid score: " << score; else { validCount ++; total += score; // total = total + score;

if (score > max) max = score; }

totalCount --;}

average = total / validCount;// Any problems?

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// validCount could be 0!

// while loop to compute max, total and validCountwhile (totalCount > 0){ …}

if (validCount > 0){ average = total / validCount; cout << endl << "max = " << max; cout << endl << "average = " << average; // cout << endl << "average = " << total / validCount;}else cout << endl << "No valid scores entered.";

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More Arithmetic Operators

validCount ++; // validCount = validCount + 1;

totalCount --; // totalCount = totalCount - 1;

total += score; // total = total + score;

total -= score; // total = total - score;

yValue /= xValue; // yValue = yValue / xValue;

yValue %= xValue; // yValue = yValue % xValue;

yValue *= xValue; // yValue = yValue * xValue;

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Example

Input an integerIf it’s positive Add it to total Otherwise Multiply it to total

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Example

While num is not positive Increment its value by 2

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Example

Input a num and add it to total until num is not positive

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Factorial

N! = 1 * 2 * 3 *…* (N - 1) * N0! = 11! = 12! = 1 * 2 = 2…5! = 1 * 2 * 3 * 4 * 5 = 120…

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Factorial

Pseudo Code

Input Num (assume Num >= 0)

Fact = 1

loopCount = 0

While loopCount < Num

loopCount ++

Fact = Fact * loopCount

Output Fact

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N! = 1 * 2 * 3 *…* (N - 1) * N

0! = 1

1! = 1

2! = 1 * 2 = 2

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5! = 1 * 2 * 3 * 4 * 5 = 120

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Factorial

Pseudo Code

Input Num Fact = 1 loopCount = Num

While loopCount > 1 Fact = Fact *

loopCount loopCount --

Output Fact

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Pseudo Code

Input Num

Fact = 1

loopCount = Num

While loopCount > 1

loopCount --

Fact = Fact * loopCount

Output Fact

Tracing Nested Loops

int xValue, yValue, zValue; xValue = 3;while (xValue > 1){ zValue = 1; yValue = xValue; while (yValue > 0) { zValue *= yValue; yValue --; } cout << "What is this: " << zValue; xValue --;}

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xValue yValue zValue ? ? ? 3 1 3 3 2 6 1 6 0 2 1 2 2 1 2 0 1

Schedule

Quiz3-2 Due 5 PM Monday Program 1 Due 9:30 PM Monday Style

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