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The Basics of Arrays
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Problem: How can the rancher easily catalog all of his cattle?
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Possible Solution
string bessie;
string mr_tongue;
string miss_fancy;
string jumper;
…
string blondie; Mr. Tongue
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New Solution: Arrays
const short HERD_SIZE=60;
string my_herd[HERD_SIZE];
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Array Allocation Syntax
base_type array_name[number of cells];
// examples
int student_numbers[50];
float student_grades[50];
string student_names[50];
const short NUM_FRIENDS = 2;
string my_friends_names[NUM_FRIENDS];
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Arrays Visualized
const int SAMPLE_SIZE=340;
float deflection_readings[SAMPLE_SIZE];
3.56 3.44 4.03 3.96 3.77 3.49 3.92 … 4.01 3.83 3.21
[0] [1] [2] [3] [4] [5] [6] … [337] [338] [339]
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Accessing Elements
deflection_readings[0]=45.1;
deflection_readings[4]=12.1;
cout << deflection_readings[6] << endl;
3.56 3.44 4.03 3.96 3.77 3.49 3.92 … 4.01 3.83 3.21
[0] [1] [2] [3] [4] [5] [6] … [337] [338] [339]
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Accessing Elements
deflection_readings[0]=45.1;
deflection_readings[4]=12.1;
cout << deflection_readings[6] << endl;
3.56 3.44 4.03 3.96 3.77 3.49 3.92 … 4.01 3.83 3.21
[0] [1] [2] [3] [4] [5] [6] … [337] [338] [339]
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Accessing Elements
deflection_readings[0]=45.1;
deflection_readings[4]=12.1;
cout << deflection_readings[6] << endl;
45.1 3.44 4.03 3.96 3.77 3.49 3.92 … 4.01 3.83 3.21
[0] [1] [2] [3] [4] [5] [6] … [337] [338] [339]
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Accessing Elements
deflection_readings[0]=45.1;
deflection_readings[4]=12.1;
cout << deflection_readings[6] << endl;
45.1 3.44 4.03 3.96 3.77 3.49 3.92 … 4.01 3.83 3.21
[0] [1] [2] [3] [4] [5] [6] … [337] [338] [339]
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Accessing Elements
deflection_readings[0]=45.1;
deflection_readings[4]=12.1;
cout << deflection_readings[6] << endl;
45.1 3.44 4.03 3.96 12.1 3.49 3.92 … 4.01 3.83 3.21
[0] [1] [2] [3] [4] [5] [6] … [337] [338] [339]
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Accessing Elements
deflection_readings[0]=45.1;
deflection_readings[4]=12.1;
cout << deflection_readings[6] << endl;
45.1 3.44 4.03 3.96 12.1 3.49 3.92 … 4.01 3.83 3.21
[0] [1] [2] [3] [4] [5] [6] … [337] [338] [339]
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Accessing Elements
deflection_readings[0]=45.1;
deflection_readings[4]=12.1;
cout << deflection_readings[6] << endl;
45.1 3.44 4.03 3.96 12.1 3.49 3.92 … 4.01 3.83 3.21
[0] [1] [2] [3] [4] [5] [6] … [337] [338] [339]
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Access Mistakes
const int SAMPLE_SIZE=340;
float deflection_readings[SAMPLE_SIZE];
...
cout << deflection_readings[SAMPLE_SIZE];
45.1 3.44 4.03 3.96 12.1 3.49 3.92 … 4.01 3.83 3.21
[0] [1] [2] [3] [4] [5] [6] … [337] [338] [339]
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Access Mistakes
const int SAMPLE_SIZE=340;
float deflection_readings[SAMPLE_SIZE];
...
cout << deflection_readings[SAMPLE_SIZE];
45.1 3.44 4.03 3.96 12.1 3.49 3.92 … 4.01 3.83 3.21
[0] [1] [2] [3] [4] [5] [6] … [337] [338] [339]
?
[340]
“Walking off the array” !! - This is not your program’s memory
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Initializing Arrays
const int SIZE=5;
int array[SIZE]={7,2,4,5,1};
7 2 4 5 1
[0] [1] [2] [3] [4]
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Initializing Arrays
const int SIZE=5;
int array[SIZE]={0};
0 0 0 0 0
[0] [1] [2] [3] [4]
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Initializing Arrays
const int SIZE=5;
int array[SIZE]={9,1};
9 1 0 0 0
[0] [1] [2] [3] [4]
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Initializing Arrays
int array[]={5,2,4};
5 2 4
[0] [1] [2]
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Things You Can NOT Do
Return an array from a function
Output an entire array like int, float, or stringsint array[10];
cout << array << endl;
Read in to an entire arrayint array[10];
cin >> array;
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Things You Can NOT Do
Return an array from a function
Output an entire array like int, float, or stringsint array[10];
cout << array << endl;
Read in to an entire arrayint array[10];
cin >> array;
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Things You Can NOT Do
Return an array from a function
Output an entire array like int, float, or stringsint array[10];
cout << array << endl;
Read in to an entire arrayint array[10];
cin >> array;
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End of Session
