Thread: 2-D Arrays (Matrices)

  1. #1
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    Question 2-D Arrays (Matrices)

    I'm confused

    I have to creat 2 matrices and then produce a third matrxi. But here is the problem that i have:

    Question states "third matrix whose all off diagonal entries are zero and the diagonal entries are the sum of first 2 matrices."

    Off diagonal? diagonal? I dotn get that

    1 3 5
    5 6 7
    7 9 9

    would diagonal be 1,6 and 9? and the rest off diagonal?

    and then i'm not really sure how to add them...so far i have:

    Code:
    void get_mat(int mat[][3]);
    void get_mat2(int matx[][3]);
    void add_mat(int mat1[][3], int mat2[][3], int mat3[][3]);
    void ptr_mat(int mat[][3]);
    
    main()
    {
    
    
    int matrix[3][3];
    int matrix1[3][3];
    int matrix2[3][3];
    
    get_mat(matrix);
    get_mat2(matrix1);
    
    add_mat(matrix, matrix1, matrix2);
    ptr_mat(matrix2);
    
    }
    
    void get_mat(int mat[][3])
    {
    int i, j;
    
    for(i=0; i<3; i++){
    for(j=0; j<3; j==){
    printf("Please enter Matrix 1 [%d][%d]", i,j)'
    scamf("%d", &mat[i][j]);
    		}
    	}
    }
    
    
    void get_mat(int mat2[][3])
    {
    int i, j;
    
    for(i=0; i<3; i++){
    for(j=0; j<3; j==){
    printf("Please enter Matrix 1 [%d][%d]", i,j)'
    scamf("%d", &mat2[i][j]);
    		}
    	}
    }

    thanks

  2. #2
    and the hat of int overfl Salem's Avatar
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    > would diagonal be 1,6 and 9? and the rest off diagonal?
    Seems about right to me, from what I can remember.

    This indexes the diagonal
    for ( i = 0 ; i < n ; i++ ) mat[i][i] = 0;
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

  3. #3
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    never mind...got it working
    Last edited by Mak; 11-27-2003 at 04:13 PM.

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