[Précédent]
[Index] | [Enoncé] | [Version imprimable]
[Prochain]

13.5
   Attrapez-les toutes... - Corrigé
Niveau 2
  
 
Fichiers:
   UtilsMatrix.java    

Voici une solution possible : 

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
 
import java.util.InputMismatchException;
import java.util.Scanner;

class CustomException extends Exception {

    public CustomException(String string) {
        super(string);
    }

}

final class UtilsMatrix {

    public static int[][] multiply(int[][] mat1, int[][] mat2) throws CustomException {

        checkMatrix(mat1);
        checkMatrix(mat2);

        int rows1 = mat1.length;
        int cols1 = mat1[0].length;
        int rows2 = mat2.length;
        int cols2 = mat2[0].length;     

        if (cols1 != rows2) {
            throw new CustomException("Matrix dimensions must fits");
        }

        int[][] result = new int[rows1][cols2];
        for (int i = 0; i < rows1; i++) {
            for (int j = 0; j < cols2; j++) {
                for (int k = 0; k < rows2; k++) {
                    result[i][j] += mat1[i][k] * mat2[k][j];
                }
            }
        }
        return result;
    }
    
    private static int tryReadInt(Scanner scanner) throws CustomException {
        int val = -1;
        try {
            val = scanner.nextInt();
        } catch (InputMismatchException e) {
            throw new CustomException("Vous devez entrez un nombre");
        }
        if (val <= 0) {
            throw new CustomException("Vous devez entrez des valeurs strictement positives !");
        }
        return val;
        
    }

    public static int[][] readMatrix() throws CustomException {
        Scanner scanner = new Scanner(System.in);
        
        int row = -1;
        int col = -1;

        System.out.println("Nouvelle matrice");
        
        System.out.print("\t Entrez nombre de lignes : ");
        row = tryReadInt(scanner);
        System.out.print("\t Entrez nombre de colonnes : ");

        col = tryReadInt(scanner);
        
        int[][] result = new int[row][col];
        for (int i = 0; i < row; i++) {
            for (int j = 0; j < col; j++) {
                System.out.print("\t Contenu cellule [" + i + "][" + j + "] : ");
                try {
                    result[i][j] = scanner.nextInt();
                } catch (InputMismatchException e) {
                    throw new CustomException("Vous devez entrez un nombre");
                }
            }
        }
        return result;
    }

    /**
     * Ensure that the matrix is not null nor empty and in the right format
     * @param mat
     * @throws CustomException
     */
    public static void checkMatrix(int[][] mat) throws CustomException {
        if (mat == null) {
            throw new CustomException("Matrix should be initialized");
        }
        if (mat.length == 0) {
            throw new CustomException("Matrix should not be empty");
        }
        int lineLength = mat[0].length;
        for (int[] lines : mat) {
            if (lineLength != lines.length){
                throw new CustomException("This is clearly not a matrix !");
            } 
        }
    }
    
    public static void display(int[][] mat) {
        for (int[] lines : mat) {
            for (int item : lines) {
                System.out.print(item + " ");
            }
            System.out.println();
        }
    }

    public static void main(String[] args) {
        int[][] mat1 = null;
        int[][] mat2 = null;
        boolean dataOk = true;
        do {
            try {
                dataOk = true;
                mat1 = readMatrix();
                mat2 = readMatrix();
            } catch (CustomException e) {
                System.err.println(e.getMessage());
                dataOk = false;
            }
        } while (!dataOk);

        int[][] prod = null;
        try {
            prod = multiply(mat1, mat2);
            display(prod);
        } catch (CustomException e) {
            System.err.println(e.getMessage());
        }
    }
}

 

[Précédent]
[Index] | [Enoncé] | [Version imprimable]
[Prochain]