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CS 1430: Programming in C++

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Quiz 1

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Functions• Function Prototype float sqrt(float x); Function name, type, parameter and parameter type

• Function Definition float sqrt(float x) { // compute and return the square root } Function Header, Body Receiving value through parameters

• Function Call root1 = (-coefB + sqrt(Delta)) / (2 * coefA);

• Function Parameters (Arguments) Formal Parameters Actual Parameters

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Write a C++ function to find and return the largest value of three integers.

Function prototype Name, Type, Parameters, Parameter Types

Function Name: Largest or LargestOfThreeInt Your choice but must be meaningful!

Function Type: int

Parameters: How many? num1, num2, num3 Data Type of each parameter int

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Function prototype

int Largest(int num1, int num2, int num3);

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// Function prototypeint Largest(int num1, int num2, int num3); // Specify types! // Formal parameters.

int main() { int score1, score2, score3, max;

cin >> score1 >> score2 >> score3;

// Call function to find the highest score max = Largest(score1, score2, score3); // Function call: No types! // Actual parameters. // Different names from formal parameters.

cout << "The largest score is " << max;

return 0; }

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Function definition// --------------------------------------------// The function finds and returns the largest // value of three integers. // --------------------------------------------int Largest(int num1, int num2, int num3) { // local variable int maxVal;

maxVal = num1;

if (num2 > maxVal) maxVal = num2;

if (num3 > maxVal) maxVal = num3;

return maxVal; }// Could be implemented in different ways// Where to get the values of num1, num2, num3?// Actual parameters at function calls.

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// Function definition // Function Header// Function bodyint Largest(int num1, int num2, int num3) { int maxVal;

maxVal = num1;

if (num2 > maxVal) maxVal = num2;

if (num3 > maxVal) maxVal = num3;

return maxVal; }

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Programming Rules

Every function, except the main function, must have a comment which describes what it does.

Other rules on functions in the future.

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// --------------------------------------------// Comment block// --------------------------------------------

// Includes

// Constants

// Function prototype int Largest(int num1, int num2, int num3);

int main() { int score1, score2, score3, max; cin >> score1 >> score2 >> score3;

max = Largest(score1, score2, score3);

cout << "The largest score is " << max;

return 0; }

// --------------------------------------------// The function finds and returns the largest // value of three integers.// --------------------------------------------int Largest(int num1, int num2, int num3) { // local variable int maxVal; … return maxVal; }

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Function Call and Control Transfer

int main(){ int score1, score2, score3, max; cin >> score1 >> score2 >> score3;

max = Largest(score1, score2, score3); cout << “Max = “ << max; return 0;}

int Largest(int num1, int num2, int num3){ int maxVal; maxVal = num1;

if (num2 > maxVal) maxVal = num2;

if (num3 > maxVal) maxVal = num3;

return maxVal;}

main() Largest()

Function call

Passing parameters

Returning to main()

With return value

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Tracing in VS

J:\Public_html\CS143\Labs\LargestByFunction

Break PointsLocalsAutos

Debug menu Start Debugging F5

Step OverTrace IntoLargest Returned

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Tracing on Paper

Input values: 53 48 60

main() Largest() score1 score2 score3 max num1 num2 num3 maxVal ? ? ? ? ? ? ? ? 53 48 60

53 48 60

53

60

60

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Schedule• Quiz4 -1 Submit to the Grader Due 10 pm Next Monday

• Lab 4

• Test 1 Friday

• Program 2 Due next Tuesday (better before Test 1) Grace: next Friday

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Using Input File• Lab 4

• Program 2

• How to do it?– Lab4 description

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How to Prepare for Test 1Test 1: Friday

60 PointsC++ Statements

TracingC++ Program

Other staff

Review Notes: 01 – 10Quizzes

LabsProg1Prog2

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DO ALL QUIZZES!

STAR PROGRAMS EARLY!

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DO NOT MISS CLASSES!