Array of arrays
Declared by use of two or more sequential [square brackets]:
data type array Name[array size 1] [array size 2] ;
Akin to N rows & columns in a spreadsheet:
| Column 0 | Column 1 | Column 2 | Column 3 | |
| Row 0 | arrayName[ 0 ][ 0 ] | arrayName[ 0 ][ 1 ] | arrayName[ 0 ][ 2 ] | arrayName[ 0 ][ 3 ] |
| Row 1 | arrayName[ 1 ][ 0 ] | arrayName[ 1 ][ 1 ] | arrayName[ 1 ][ 2 ] | arrayName[ 1 ][ 3 ] |
| Row 2 | arrayName[ 2 ][ 0 ] | arrayName[ 2 ][ 1 ] | arrayName[ 2 ][ 2 ] | arrayName[ 2 ][ 3 ] |
int myMultiArray[ 3 ] [ 4 ] ; //declares a two dimensional array called myMultiArray that contains 6 elements; e.g. in 3 rows / 4 columns
Defined by assiging values, separated by a comma, within {curly braces} for each dimension:
int myMultiArray[ 3 ] [ 4 ] = { { 0, 1, 2, 3 }, { 4, 5, 6, 7 }, { 8, 9, 10, 11 } } ; //same as:
int myMultiArray[ 3 ] [ 4 ] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 } ; //no need for nested curly braces
Single values can be defined by assigning the value to the specific element number, starting from zero for each dimension!
myMultiArray[ 2 ] [ 2 ] = 42 ; //sets the element in row 2, column 2 to 42
Specific elements can be accessed by assigning an array element to a variable
int myVar = myArray[ 1 ] [ 3 ] ; //assigns myVar with the element contained in row 1, column 3
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 |
#include <stdio.h> int main() { int myMultiArray[ 3 ] [ 4 ] = { { 0, 1, 2, 3 }, { 4, 5, 6, 7 }, { 8, 9, 10, 11 } } ; printf("Element [2][2] is: %dn", myMultiArray[2][2]) ; myMultiArray[ 2 ] [ 2 ] = 42 ; printf("Element [2][2] is now: %dn", myMultiArray[2][2]) ; int myVar = myMultiArray[2][2] ; printf("myVar has now been assigned the [2][2] element: %dn", myVar) ; return 0; } |
Compile & run:
| Element [2][2] is: 10 Element [2][2] is now: 42 myVar has now been assigned the [2][2] element: 42 |