: In function 'int main()':
:11:52: error: invalid types 'int[int]' for array subscript
   11 |                         for(int j=0;j<b;j++) cin>>a[i][j];
      |                                                    ^
:14:36: error: invalid types 'int[int]' for array subscript
   14 |                         rowmax[i]=a[i][0];
      |                                    ^
:16:47: error: invalid types 'int[int]' for array subscript
   16 |                                 if(rowmax[i]<a[i][j]) rowmax[i]=a[i][j];
      |                                               ^
:16:66: error: invalid types 'int[int]' for array subscript
   16 |                                 if(rowmax[i]<a[i][j]) rowmax[i]=a[i][j];
      |                                                                  ^
:20:39: error: invalid types 'int[int]' for array subscript
   20 |                         columnmin[i]=a[0][i];
      |                                       ^
:22:50: error: invalid types 'int[int]' for array subscript
   22 |                                 if(columnmin[i]>a[j][i]) columnmin[i]=a[j][i];
      |                                                  ^
:22:72: error: invalid types 'int[int]' for array subscript
   22 |                                 if(columnmin[i]>a[j][i]) columnmin[i]=a[j][i];
      |                                                                        ^