boolean - Find coords of the largest rectangle in bool array -

i have problem. let's assume have matrix of 1's , 0's , want find largest rectangle in consists of 1's. code below , computes area , stores in variable "res". question is, how can coords of rectangle in matrix? mean x,y,h,w. x,y start coords , h,w(height,width) size of rectangle. kind of lost. reply.

       int maximalrectangle(vector<vector<char> > &matrix)     {         int row = matrix.size();         if (row==0){return 0;}         int col = matrix[0].size();         int res=0;         vector<vector<int>> ones(row,vector<int>(col,0));          (int i=0;i<row;i++){             for(int j=0;j<col;j++){                 if (matrix[i][j]=='1'){                      if (j==0){ones[i][j]=1;}                     else{ones[i][j]=ones[i][j-1]+1;}                 }             }         }          (int i=0;i<row;i++){             for(int j=0;j<col;j++){                 if (ones[i][j]!=0){                      int h = i-1;                     int tmp=ones[i][j];                     int mini=ones[i][j];                     while (h>=0){                         if (ones[h][j]==0){                             break;                         }else{                             if (ones[h][j]<mini){                                 mini = ones[h][j];                             }                             if (tmp< mini*(i-h+1)){                                 tmp= mini*(i-h+1);                             }                             h--;                         }                     }                     if (res<tmp){                         res=tmp;                     }                 }             }         }          return res;     }