C++ Tutorial - About Pointers

// ex5.cpp

#include <string>
using namespace std;

const maxrows=5;
const maxcolumns=10;

struct mapitem
{
  int row,column;
  string line;
  mapitem(int _row,int _column) {row=_row,column=_column,line='\0';}
};

typedef mapitem * col[maxcolumns];
typedef col * gridtype[maxrows];

int main(int argc, char* argv[])
{
  gridtype grid;
  int rowindex,colindex;

  for (rowindex=0;rowindex < maxrows; rowindex++) {
  // Allocate memory for columns in each row
    grid[rowindex] = new col[maxcolumns];
    for (colindex=0;colindex < maxcolumns;colindex++)
    {
    // Hook up the grid to a new item
    *(grid[rowindex])[colindex] = new mapitem(rowindex,colindex) ;
    }
  }

  // Set the string for the top left corner etc
  (*grid[0][0])->line="Top Left Corner";
  (*grid[maxrows-1][0])->line="Bottom Left Corner";
  (*grid[0][maxcolumns-1])->line="Top Right Corner";
  (*grid[maxrows-1][maxcolumns-1])->line="Bottom Right Corner";
  return 0;
}

1. Each Row.
2. Each Item in each row.

This completes this lesson. The next lesson will be on the advanced users of pointers.

• Learn About Pointers
• Allocating Memory in C++
• Explanation of Example 1 Continued
• Explanation of Example 1 Continued
• Examples of Pointers
• Learn About Using Pointers
• An Example Using New and Delete
• Some Rules for Working with Pointers
• Some More Examples of Pointers in C++
• Example of 2D Structure with Pointers