Definition
, for example:
float a [3] [4], b [5] [10];
Definition A is an array of 3 * 4 (3 lines 4 columns), B is an array of 5 * 10 (5 lines 10 columns). Note that
float a [3, 4], b [5, 10];
is not easy to understand, a C language program and its operation results:
#include int main (int Argc, const char * argv []) {int Array [3] [5] = {0}; // Define a twodimensional array (3 rows 5 columns) int Temp = 0 ; // Set a temporary integer variable to assign a value for the array for (int A = 0; aoperation result is (for easy viewing, finishing into a table):
array [0] [0] = 1  array [0] [1] = 2 < / p>  array [0] [2] = 3  array [0] [3] = 4  array [0] [4] = 5  
array [1] [0] = 6  array [1] [1] = 7  Array [1] [2] = 8  array [1] [3] = 9  array [1] [4] = 10  
array [2] [1] = 12  array [2] [2] = 13  array [2] [3] = 14 < / p>  array [2] [4] = 15 
overview
Twodimensional array a [m] [n], this is a M line, Ncolumn twodimensional array. Set a [P] [q] for a first element of A, that is, twodimensional array The subscript from P to M + P, column subscript from q to n + q, press "Row priority order" storage When it is stored, the address of element a [i] [j] is calculated as:
LOC (a [i] [ J]) = LOC (a [p] [q]) + (i  p) * n + (j  q)) * t
When storing by "column priority order", the address is calculated To:
LOC (a [i] [j]) = LOC (a [p] [q]) + ((j  q) * m + (i  p)) * t
Store at least the number of cells required (MP + 1) * (NQ + 1) * T bybyte
Basic operation
Transposition matrix
// wherein A, B is M * N matrix:
void track (Matrix A, Matrix B) {INT I, J; for (i = 0; Imatrix phase Add
//) A, B, C is M * N matrix: Void AddMat (Matrix C, Matrix A, Matrix B) {INT I, J; for (i = 0; Imatrix multiplied
// wherein A is M * n matrix, B is N * 1 matrix, C is M * 1 matrix Void Mutmat (Matrix C, Matrix A, Matrix B ) {INT I, J, K; For (i = 0; irelated concept
C ++ dynamic 2D array:
to shaping For example, the ROW is the number of rows, and the COL is the number of numbers
int ** data; // stores a 2D array pointer (pointing to the pointer to the pointer. Date = x [0] [0] of the address. Such a standard is better. Because Sizeof (Date) result is 4 不 不 二 二 数 数 组)
// The following implementation How to apply for a memory Data = new int * [rot]; for (int K = 0; k// Assignment, for example, DATA [0] [0] = 5; // = 5 = 5 = 5 (called 0 row 0 columns in C ++) to 5 // Delete Memory for (int) i = 0; ISee
matrix

matrix

sparse matrix