3. (4) .
.
1) , . double dArray[13][12] dArray double 13×12 , .. 13 12 .
2) . , . , n. , n <= 20 20×20. n <= 20.
3) . , dArray 0 12 0 11 .
4) for. dArray:
int i, j;
for (i = 0; i < 13; i++)
{
for (j = 0; j < 12; j++)
{
dArray[i][j] = 0;
}
}
5) .
, dArray , . : 100 +200. :
srand((unsigned)time(NULL));
int i, j;
for (i = 0; i < 13; i++)
{
for (j = 0; j < 12; j++)
{
dArray[i][j] = (300. * rand() / RAND_MAX) - 100;
}
}
6) , , ..
.
(), () .
= (ij), = (ji).
, m × n, n × m.
3
.
:
[ m × n ] .
:
M [ n × m ] .
:
i, j .
1. [ i ]. 2 i = 0,, n 1 .
2. [ j ]. 3 j = 0,, m 1.
|
|
3. [ [ i,j ]]. [ i, j ] = [ j, i ]. ( )
() . = (ij) = (bij) m × n = + , ij = aij + bij i = 1,2,..., m; j = 1,2,, n (.. ).
4
.
:
[ m × n ], [ m × n ] .
:
[ m × n ] .
:
i, j .
1. [ i ]. 2 i = 0,, m 1 .
2. [ j ]. 3 j = 0,, n 1.
3. [ [ i,j ]]. [ i,j ] = [ i, j ] + [ i, j ].
, .
= (ij) m × n = (bij) n × p, × m × p. ( m × p) , i j :
5
.
:
[ m × n ], [ n × p ] .
:
[ m × p ] .
:
i, j, k .
1. [ i ]. 2 i = 0,, m 1 .
2. [ j ]. 3 4 j = 0,, p 1.
3. [ [ i,j ]]. [ i,j ] = 0.
4. [ k ]. 5 k = 0,, n 1.
5. [ [ i,j ]]. [ i,j ] = [ i,j ] + [ i, k ] * [ k, j ].
4
1. m × n. m n . 4.1 .
2. m × n. m n . 4.1 .
3. m × n n × p. m, n, . 4.2 .
.
! , .
4.1. 1 2
m, n | m, n | m, n | |||
m = 2; n = 3 | m = 3; n = 5 | m = 5; n = 2 | |||
m = 2; n = 4 | m = 3; n = 6 | m = 5; n = 3 | |||
m = 2; n = 5 | m = 4; n = 2 | m = 5; n = 4 | |||
m = 2; n = 6 | m = 4; n = 3 | m = 5; n = 5 | |||
m = 3; n = 2 | m = 4; n = 4 | m = 5; n = 6 | |||
m = 3; n = 3 | m = 4; n = 5 | m = 6; n = 2 | |||
m = 3; n = 4 | m = 4; n = 6 |
|
|
4.2. 3
m, n, p | m, n, p | ||
m = 2; n = 2; = 2 | m = 4; n = 4; = 4 | ||
m = 3; n = 2; = 2 | m = 5; n = 4; = 4 | ||
m = 4; n = 2; = 2 | m = 2; n = 4; = 5 | ||
m = 5; n = 2; = 2 | m = 3; n = 4; = 5 | ||
m = 2; n = 3; = 3 | m = 4; n = 4; = 5 | ||
m = 3; n = 3; = 3 | m = 5; n = 4; = 5 | ||
m = 4; n = 3; = 3 | m = 2; n = 4; = 6 | ||
m = 5; n = 3; = 3 | m = 3; n = 4; = 6 | ||
m = 2; n = 4; = 4 | m = 4; n = 4; = 6 | ||
m = 3; n = 4; = 4 | m = 5; n = 4; = 6 |
:
= * + D
A, B, C, D .
?
5
: .
:
1) ++.
2) .