Programming Forums > Application Development > C++

Gunman · Oct 17th, 2005, 3:46 AM

Hey can someone kinda of explain to me about arrays ? I have information about arrays but can't really understand them . I would like to know some basic uses of array and how and when they are used..and about one dimensional and two dimensional arrays . Thanks =)

Polyphemus_ · Oct 17th, 2005, 4:12 AM

Here is an example of a one-dimensional array:

(Toggle Plain Text)

int array[10]; // create an array, containing 10 integers

array[0] = 8; // assign the value 8 to the first element of the array (array indexes start always at 0!)
array[1] = 3; // assign the value 3 to the second element of the array
array[5] = 263; // assign the value 263 to the sixth element of the array

and an example of a two-dimensional array:

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int array[10][5]; // create an array, containing 10 arrays, each containing 5 integers

array[0][3] = 173; // assign the value 173 to the fourth element of the first array
array[6][0] = 3245; // assign the value 3245 to the first element of the seventh array
array[8][3] = 632; // assign the value 632 to the fourth element of the 9th array

hope this helps

Gunman · Oct 17th, 2005, 4:34 AM

Okay so what are arrays used for ? Thanks for help

Polyphemus_ · Oct 17th, 2005, 4:38 AM

Arrays are basically used to store a series of values of the same category. They are also often used for an amount of data you don't know the size of when compiling - e.g. information read from a file. You can use dynamic memory allocation then - asking memory at runtime. If you want, i can also give you an example of that

.

Gunman · Oct 17th, 2005, 4:46 AM

Okay sure ..=)

Polyphemus_ · Oct 17th, 2005, 5:28 AM

(Toggle Plain Text)

int arraysize = 20; // this is the size of the array

int *array = new int[arraysize]; // create the pointer array, and let it point to memory for an array

array[0] = 8; // you know this part already

Gunman · Oct 17th, 2005, 6:37 AM

Thanks think i understood it ..=)

DaWei · Oct 17th, 2005, 6:46 AM

"This little thingy between the quotation marks is a sequential collection of characters. It could be stored in an array."

If that were stored in MyArray, MyArray [0] would contain "T" and MyArray [12] would contain "t". If you marked the end by adding a byte with the value, 0, it would actually constitute a C string. Simple, and useful.

Gunman · Oct 18th, 2005, 12:00 AM

Hey ..I found this code on the web but can't understand how it works..
Thanks for help.

#include <iostream>

using namespace std;

int main()
{
int x;
int y;
int array[8][8]; // Declares an array like a chessboard

for ( x = 0; x < 8; x++ ) {
for ( y = 0; y < 8; y++ )
array[x][y] = x * y; // Set each element to a value
}
cout<<"Array Indices:\n";
for ( x = 0; x < 8;x++ ) {
for ( y = 0; y < 8; y++ )
cout<<"["<<x<<"]["<<y<<"]="<< array[x][y] <<" ";
cout<<"\n";
}
cin.get();
}

stevengs · Oct 18th, 2005, 3:33 AM

you refuse to use CODE tags?

Oct 17th, 2005, 3:46 AM	#1
Gunman Programmer Join Date: Oct 2005 Posts: 56 Rep Power: 3	Arrays Hey can someone kinda of explain to me about arrays ? I have information about arrays but can't really understand them . I would like to know some basic uses of array and how and when they are used..and about one dimensional and two dimensional arrays . Thanks =)

Oct 17th, 2005, 4:12 AM	#2
Polyphemus_ Expert Programmer Join Date: Aug 2005 Location: Rotterdam, the Netherlands Posts: 942 Rep Power: 4	Here is an example of a one-dimensional array: (Toggle Plain Text) int array[10]; // create an array, containing 10 integers array[0] = 8; // assign the value 8 to the first element of the array (array indexes start always at 0!) array[1] = 3; // assign the value 3 to the second element of the array array[5] = 263; // assign the value 263 to the sixth element of the array int array[10]; // create an array, containing 10 integers array[0] = 8; // assign the value 8 to the first element of the array (array indexes start always at 0!) array[1] = 3; // assign the value 3 to the second element of the array array[5] = 263; // assign the value 263 to the sixth element of the array and an example of a two-dimensional array: (Toggle Plain Text) int array[10][5]; // create an array, containing 10 arrays, each containing 5 integers array[0][3] = 173; // assign the value 173 to the fourth element of the first array array[6][0] = 3245; // assign the value 3245 to the first element of the seventh array array[8][3] = 632; // assign the value 632 to the fourth element of the 9th array int array[10][5]; // create an array, containing 10 arrays, each containing 5 integers array[0][3] = 173; // assign the value 173 to the fourth element of the first array array[6][0] = 3245; // assign the value 3245 to the first element of the seventh array array[8][3] = 632; // assign the value 632 to the fourth element of the 9th array hope this helps

Oct 17th, 2005, 5:28 AM	#6
Polyphemus_ Expert Programmer Join Date: Aug 2005 Location: Rotterdam, the Netherlands Posts: 942 Rep Power: 4	(Toggle Plain Text) int arraysize = 20; // this is the size of the array int array = new int[arraysize]; // create the pointer array, and let it point to memory for an array array[0] = 8; // you know this part already int arraysize = 20; // this is the size of the array int array = new int[arraysize]; // create the pointer array, and let it point to memory for an array array[0] = 8; // you know this part already

Oct 17th, 2005, 6:46 AM	#8
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	"This little thingy between the quotation marks is a sequential collection of characters. It could be stored in an array." If that were stored in MyArray, MyArray [0] would contain "T" and MyArray [12] would contain "t". If you marked the end by adding a byte with the value, 0, it would actually constitute a C string. Simple, and useful. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

Oct 18th, 2005, 3:33 AM	#10
stevengs Professional Programmer Join Date: May 2005 Location: Bad Nauheim, Germany Posts: 436 Rep Power: 4	you refuse to use CODE tags? __________________ -Steven "Is this a piece of your brain?" - Basil Fawlty

Oct 17th, 2005, 4:34 AM	#3
Gunman Programmer Join Date: Oct 2005 Posts: 56 Rep Power: 3	Okay so what are arrays used for ? Thanks for help

Oct 17th, 2005, 4:38 AM	#4
Polyphemus_ Expert Programmer Join Date: Aug 2005 Location: Rotterdam, the Netherlands Posts: 942 Rep Power: 4	Arrays are basically used to store a series of values of the same category. They are also often used for an amount of data you don't know the size of when compiling - e.g. information read from a file. You can use dynamic memory allocation then - asking memory at runtime. If you want, i can also give you an example of that .

Oct 17th, 2005, 4:46 AM	#5
Gunman Programmer Join Date: Oct 2005 Posts: 56 Rep Power: 3	Okay sure ..=)

Oct 17th, 2005, 6:37 AM	#7
Gunman Programmer Join Date: Oct 2005 Posts: 56 Rep Power: 3	Thanks think i understood it ..=)

Oct 18th, 2005, 12:00 AM	#9
Gunman Programmer Join Date: Oct 2005 Posts: 56 Rep Power: 3	Hey ..I found this code on the web but can't understand how it works.. Thanks for help. #include <iostream> using namespace std; int main() { int x; int y; int array[8][8]; // Declares an array like a chessboard for ( x = 0; x < 8; x++ ) { for ( y = 0; y < 8; y++ ) array[x][y] = x * y; // Set each element to a value } cout<<"Array Indices:\n"; for ( x = 0; x < 8;x++ ) { for ( y = 0; y < 8; y++ ) cout<<"["<<x<<"]["<<y<<"]="<< array[x][y] <<" "; cout<<"\n"; } cin.get(); }

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