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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <string.h>
  4. #include <math.h>
  5.  
  6. void det_calc(double *matrix, int pivot[], int dim){
  7.     int m, n, p;
  8.     double *mat, *row, *col, max;
  9.     mat = matrix;
  10.     for (p = 0; p < dim; mat += dim, p++){ // Get the pivot
  11.         pivot[p] = p;
  12.         max = fabs(*(mat + p));
  13.         row = mat + dim;
  14.         for (n = p + 1; n < dim; n++, row += dim){
  15.             if (max < fabs(*(row + p))){
  16.                 max = fabs(*(row + p));
  17.                 pivot[p] = n;
  18.                 col = row;
  19.             }
  20.         }
  21.         if (pivot[p] != p) // If pivot is diff from current row, swap
  22.             for (n = 0; n < dim; n++){
  23.                 max = *(mat + n);
  24.                 *(mat + n) = *(col + n);
  25.                 *(col + n) = max;
  26.             }
  27.         if (*(mat + p) == 0) return; // Singular matrix
  28.         row = mat + dim;
  29.         for (m = p + 1; m < dim; row += dim, m++) // Get lower triangular matrix
  30.             *(row + p) /= *(mat + p);
  31.         row = mat + dim;
  32.         for (m = p + 1; m < dim; row += dim, m++) // Update matrix
  33.             for (n = p + 1; n < dim; n++)
  34.                 *(row + n) -= *(row + p) * *(mat + n);
  35.     }
  36. }
  37.  
  38. double* getRow(int size){
  39.     double* row = malloc(size*sizeof(double));
  40.     for (int i = 0; i < size; i++) scanf("%f", row+i);
  41.     return row;
  42. }
  43.  
  44. int main(void){
  45.     int dim, count = 0;
  46.     double result = 1.0, test, numArr[3];
  47.     char line[100];
  48.     char *p = line, *beginning = p;
  49.     // fgets(line, sizeof(line), stdin); // Get the first number
  50.     scanf("%d", &dim); // Convert to int
  51.     double* matrix[dim];
  52.     int pivot[dim]; // Array to track pivot
  53.     for (int i = 0; i < dim; i++){
  54.         matrix[i] = getRow(dim);
  55.     }
  56.     printf("Dim = %d\n", dim);
  57.     for (int i = 0; i < dim; i++){
  58.         for (int j = 0; j < dim; j++){
  59.             printf("%.1f ", matrix[i][j]);
  60.         } printf("\n");
  61.     }
  62.     /*det_calc(&matrix[0][0], pivot, dim);
  63.     for(int i = 0; i < dim; i++) result *= matrix[i][i];
  64.     printf("%f", result);*/
  65.     return 0;
  66. }
Success #stdin #stdout 0s 5380KB
comments (?)
stdin
copy 
9
0 0 0 0 0 0 2 3 1
0 0 0 7 3 2 3 3 1
0 0 0 0 9 10 2 8 3
0 0 0 0 0 0 0 6 4
0 4 7 10 5 10 5 9 6
0 0 0 0 0 3 9 9 6
2 1 2 1 7 6 3 10 9
0 0 5 7 7 3 10 2 5
0 0 0 0 0 0 0 0 5
stdout
copy 
Dim = 9
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
https://ideone.com/Ph9Gc9
language:
C (gcc 8.3)
created:
1 year ago
visibility:
public

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