Declaration of Variables

Declaration of Variablesint scoreCount; float score, total;char grade;string courseName;bool validInput;

// Memory Allocation// Address for each variable// Size for each data type// int : 2 bytes// float : 4 bytes// char : 1 byte// string: # of chars plus one

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Computing Highest, Lowest, Average

float score;

float total, max, min, avg;

int scoreCount;

// Using one variable to input and process scores

// One score at a time

// When do we need to keep all scores?

// Is my score below or above the average?

// How do we keep all scores?

// Array!

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Declaration of Arraysfloat scores[100];// 100 floats

char chs[20];// 20 chars

int nums[30]; // 30 integers

string allNames[100];// 100 strings

bool prog3Completed[26];// 26 bool values

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Memory Allocation for Array

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nums

int nums[30];// 30 integers// Address: the first element// How many bytes?// 30 * 2: 60 bytes

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Array Size Must Be Constant Expressionsconst int MAX_SIZE = 30;

int size = 30;

int nums[30];float ArrayA[MAX_SIZE]; // Valid?// Yes!// number of bytes?

float ArrayB[size]; // Valid?// NO!

float ArrayC[MAX_SIZE * 10]; //Valid?// Yes!// number of bytes?

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Array Index and Array Element

• How to access array elements?

• Use array index to specify array element

• Index of any array begins with 0

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Array Element and Array Index

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Array Element

Array Indices

int nums[30];

Array Element

nums[0] nums[1] nums[29]7

Operations on Array Elements

• An array element is the same as a single variable

• Operations on array elements:

Input

Output

Arithmetic operations

Assignment

Comparison

Function parameters

…

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int nums[30];

// Read an integer and store it in the 1st element of nums.

cin >> nums[0];

// Incement the 1st element of nums by one.nums[0] ++;

// Assign the value of the 1st element of nums to // the 2nd element of nums.nums[1] = nums[0];

// Incement the 2nd element of nums by the value of size.nums[1] += size;

// Set the last element of nums to the value of size.nums[29] = size;

// Assign the value of the 16th element of nums to size.size = nums[15];

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int nums[30];

// Display 1st element of nums with a width of 9.cout << endl << setw(9) << nums[0];

// Compute the average of the 1st and last elements of // nums and store it in avg.avg = (nums[0] + nums[29]) / 2.0;

// If the 2nd element is not zero, display the float // quotient of 1st element divided by 2nd.if (nums[1] != 0) cout << "Quotient = " << float(nums[0]) / nums[1];

// Call function Largest to find the max value between // the first three elments of nums and store it in Max.// Function prototype: // int Largest(int num1, int num2, int num3);Max = Largest(nums[0], nums[1], nums[2]);

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const int MAX_SIZE = 30;

int nums[MAX_SIZE], index;

cin >> nums[29];

// Valid?

cin >> nums[30];

// Valid?

cout << nums[MAX_SIZE - 1];

// Valid?

cout << nums[MAX_SIZE];

// Valid?

cin >> index;

if (index < MAX_SIZE && index >= 0)

nums[index] = nums[10];

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Initializing Arrays in Declarations

int agae[5] = {23, 19, 33, 45, 60};

float temperature[] = {0.0, 112.37, -12, 98.6};

// May not working in HiC

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Input n Numbers to an Array

int ArrayA[30];

cin >> ArrayA[0];cin >> ArrayA[1];cin >> ArrayA[2];cin >> ArrayA[3];

...cin >> ArrayA[29];

cin >> ArrayA[30];

// OK?13

Use while Loop to Process Array const int MAX_SIZE = 30;

int ArrayA[MAX_SIZE];

int size = 20;

int index = 0;

// Loop 20 times

while (index < size)

{

cin >> ArrayA[index];

index ++;

}

//Count-Controlled Loop 14

Use For Loops to Process Arrays

cin >> size;

// Assume size in the range

// Input to an array

for (int i = 0; i < size; i ++)

cin >> ArrayA[i];

// Same as while loop

// Must Use For Loops for Arrays!

cin >> size;

// Assume in the range

// Input to an array

int i = 0;

while (i < size)

{

cin >> ArrayA[i];

++ i;

}

// Four parts of a loop!

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Use For Loops to Process Arrays

// Must use For loop for arrays!

for (int i = 0; i < size; i ++)

cin >> ArrayA[i];

How many times is the body executed?

size times!

(Zero times if size <= 0)

Initialize Test

Body Update

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Use For Loops to Process Arrays

int ArrayA[30], size, j;

cin >> size; // Assume size is between 1 and 30

// Input to an array for (int i = 0; i < size; i ++) cin >> ArrayA[i];

// Output array for (j = 0; j < size; j ++) cout << endl << setw(8) << ArrayA[j];

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Use For Loops to Process Arrays int ArrayA[30], size, j;

cin >> size; for (int i = 0; i < size; i ++) cin >> ArrayA[i];

// Compute total , max, min// The range is known.int min = 60;int max = 0;int total = 0;

for (j = 0; j < size; j ++) { total += ArrayA[j];

if (ArrayA[j] > max) max = ArrayA[j];

if (ArrayA[j] < min) min = ArrayA[j];}

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Use For Loops to Process Arrays int ArrayA[30], size;

cin >> size; for (int i = 0; i < size; i ++) cin >> ArrayA[i];

// Compute total , max, min// The range is NOT known.// size > 0 and size <= 30int min = ArrayA[0];int max = ArrayA[0];int total = ArrayA[0];

for (int j = 1; j < size; j ++) { total += ArrayA[j];

if (ArrayA[j] > max) max = ArrayA[j];

if (ArrayA[j] < min) min = ArrayA[j];}

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Never go out of the range of an array

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const int MAX_SIZE = 30;

int ArrayA[MAX_SIZE];

for (int i = 1; i <= MAX_SIZE; i ++)

cin >> ArrayA[i];

// Out of Range!

0 1 2 3 28 29

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Schedule

Drop your Prog3.cpp to

S:\Courses\CSSE\yangq\CS1430\Prog3

Quiz5-1 (1 point)

Due: 5 PM Wednesday

Program 3

Due 9:30 PM Wednesday, March 2321