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POC creating a matrix using pointers and then copying elements from the matrix
 

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  1. POC creating a matrix using pointers and then copying elements from the matrix
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    <p>Im trying to use a function to copy a row of a matrix and return a pointer to that row, then print that row, but my get_row() function is failing, any help would be most appreciated, random data is a specified piece of the program, i will then have to get a column, transpose and sub matrix the same way, but i hope if i understand how to do it for get_row() ill be able to do the rest: </p> <p>my algorithm in get_row() is wrong here is my code:</p> <p>my main(revised):</p> <pre><code>int main() { int m,n,t,check; double **mat,*matc; check = 0 ; while ( check != 2 ) { printf("\nEnter the size of your matrix m x n in the form m,n : " ); check = scanf( "%d, %d", &amp;m, &amp;n ); _flushall() ; }; int row; mat = (double **) malloc(m * sizeof(double*)) ; for(row = 0; row&lt;m; row++) { mat[row] = (double *) malloc(n * sizeof(double)); } srand((unsigned int) time(NULL)); *rand_matrix(*mat,m,n); print_matrix(*mat,m,n); check = 0 ; while ( check != 1 ) { printf("\nEnter the row you would like to see : " ); check = scanf( "%d", &amp;t ); _flushall() ; }; *matc=*get_row(*mat,n,t); print_matrix(matc,4,n); check = 0 ; while ( check != 1 ) { printf("\nEnter the column you would like to see : " ); check = scanf( "%d", &amp;t ); _flushall() ; } printf("\nMatrix column: [%d]\n",t); get_column( *mat,m, n, t); getch(); transpose( *mat, n, m); getch(); free(mat); } </code></pre> <p>These are the functions im using, have a look at get_row(), and check if you can spot what im doing wrong, cheers</p> <pre><code>//FUNCTION TO POPULATE MATRIX WITH RANDOM DOUBLES double *rand_matrix( double *mat, int m, int n) { double *usermat=mat; int i; for (i=0;i&lt;m*n;i++) { *usermat++=i+1; //populates with 1 to m*n } return mat; } //PRINTS MATRIX void print_matrix( double *mat, int m, int n) { int i,j; printf("\nMatrix dimensions: [%d,%d]\n",m,n); double *usermat=mat; for (i=0;i&lt;m;i++) { usermat=(mat+i*n); for (j=0;j&lt;n;j++) { printf(" %0.2lf ",*usermat++); } printf("\n"); } } //GET ROW double *get_row( double *mat, int n,int t) { int i,j; printf("\nMatrix row: [%d]\n",t); double *usermat=mat; printf("\n"); usermat=(mat+n*(t-1)); for (j=0;j&lt;n;j++) { *usermat++; } printf("\n"); return usermat; } </code></pre>
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    1. USEoin Murray
    1. USEoin Murray
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    1. COWhat happens when you run you program? What do you expect to happen? To simplify testing and debugging, do not use random data. Like fill each row in the matrix with a single value (0, 1, 2... to rows-1, for example.)
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      1. POC creating a matrix using pointers and then copying elements from the matrix
      1. USSome programmer dude
    2. COapologies for not specifying, specified in the problem i must solve with this program is that random data must be used.
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      1. POC creating a matrix using pointers and then copying elements from the matrix
      1. USEoin Murray
    3. COYou can use random data in the real program, and non-random data while testing. You can use the pre-processor to check for something like a `DEBUG` macro that is only defined when you build for yourself.
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      1. POC creating a matrix using pointers and then copying elements from the matrix
      1. USSome programmer dude
 

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