1: /* matrix00mul.c */
 2: #include <stdio.h>
 3: 
 4: int main( void ){
 5: 
 6:   /* 変数の宣言 */
 7:   int n, l, m;
 8: 
 9:   n = 2;
10:   l = 3;
11:   m = 2;
12: 
13:   /* 配列変数の宣言 */
14:   float a[ n ][ l ], b[ l ][ m ], c[ n ][ m ];
15: 
16:   /* カウンタ用変数の宣言 */
17:   int i, j, k;
18: 
19:   /* 配列の初期化 */
20:   a[ 0 ][ 0 ] = 2.3; a[ 0 ][ 1 ] = 0.2; a[ 0 ][ 2 ] = 0.1;
21:   a[ 1 ][ 0 ] = -0.3; a[ 1 ][ 1 ] = 0.0; a[ 1 ][ 2 ] = -0.5;
22: 
23:   b[ 0 ][ 0 ] = -1.0; b[ 0 ][ 1 ] = -0.1;
24:   b[ 1 ][ 0 ] = 0; b[ 1 ][ 1 ] = 2.2;
25:   b[ 2 ][ 0 ] = 0.5; b[ 2 ][ 1 ] = 0.7;
26: 
27:   /* 行列の積を計算 */
28:   for ( i = 0; i < n; i = i + 1 ) {
29:     for ( j = 0; j < m; j = j + 1 ) {
30:       c[ i ][ j ] = 0;
31:       for ( k = 0; k < l; k = k + 1 ) {
32:         
33:         c[ i ][ j ] = c[ i ][ j ] + ( a[ i ][ k ] * b[ k ][ j ] );
34: 
35:       }
36:     }
37:   }
38: 
39:   /* 行列 a の表示 */
40:   printf( " a =\n" );
41:   for ( i = 0; i < n; i = i + 1 ) {
42:     printf( " [" );
43:     for ( j = 0; j < l; j = j + 1 ) {
44: 
45:       printf( " %5.2f ", a[ i ][ j ] );
46: 
47:     }
48:     printf( "]\n" );
49:   }
50:   printf( "\n" );
51: 
52:   /* 行列 b の表示 */
53:   printf( " b =\n" );
54:   for ( i = 0; i < l; i = i + 1 ) {
55:     printf( " [" );
56:     for ( j = 0; j < m; j = j + 1 ) {
57:       
58:       printf( " %5.2f ", b[ i ][ j ] );
59:       
60:     }
61:     printf( "]\n" );
62:   }
63:   printf( "\n" );
64:   
65:   /* 行列 c の表示 */
66:   printf( " c = a + b\n" );
67:   for ( i = 0; i < n; i = i + 1 ) {
68:     printf( " [" );
69:     for ( j = 0; j < m; j = j + 1 ) {
70: 
71:       printf( " %5.2f ", c[ i ][ j ] );
72: 
73:     }
74:     printf( "]\n" );
75:   }
76:   printf( "\n" );
77:   
78: }