Arrays
| Simple
static array.
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// A simple static array.
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const
int SZ=3; // constant
int i, array[SZ];
// initialise
for(i=0; i<SZ; i++) array[i]=i;
// print
for(i=0; i<SZ; i++) cout<<array[i];
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A constant must be used for the subscript .
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Simple dynamic array.
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// A simple dynamic array.
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int
i, var=10;
int* array = new int[var];
// initialise
for(i=0;i<var;i++) array[i]=i;
// print
for(i=0;i<var;i++) cout<<array[i];
delete array;
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Note that a variable can be used as a subscript.
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Simple static matrix.
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// A simple static matrix.
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const int SZ=3;
int i, j;
int array [SZ] [SZ];
//initialise
for(i=0 ;i<SZ ;i++)
for(j=0 ;j<SZ ;j++) array[i]
[j] =j;
// print
for(i=0 ;i<SZ ;i++)
for(j=0 ;j<SZ ;j++) cout<<array[i]
[j];
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Dynamic matrix.
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// Only one subscript need be specified at runtime.
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const int SZ=3;
int var=4, i, j;
int (*matrix)[SZ] = new
int[var] [SZ];
for(i=0; i<var; i++)
for(j=0; j<SZ; j++) matrix[i]
[j] =j;
for(i=0; i<var; i++)
for(j=0; j<SZ; j++) cout<<matrix[i]
[j];
delete [] matrix;
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Dynamic Matrix.
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// Dynamic matrix.
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int
i, rows=2, cols=3;
int**matrix
=new
int*[rows];
for(i=0; i< rows; i++) matrix[i]=
new int[cols];
// initialise
for(i=0; i<rows; i++)
for(int j=0; j<cols; j++)
matrix[i] [j] =j;
// print
for(i=0; i<rows; i++)
for(int j=0; j<cols; j++)
cout<<matrix[i] [j];
// delete
for(i=rows;i>0; --i) delete
[] matrix [i-1];
delete [] matrix;
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This defines a 2 x 3 matrix.
It is allocated totally from the free store and
both subscripts can be specified at runtime.
The line int** matrix =new int*[rows]; is
key.
It means: a pointer to an array of ints with rows
elements is assigned to matrix which is a pointer
to a pointer to int.
Simple huh?... Isn't C++ fun :).
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-
An Array Class using overloaded
operators and the STL exception
handling
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A Vector Class using a method
based implementation and custom
exception handling
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