Unique Paths Count

A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below).
The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked 'Finish' in the diagram below).
How many possible unique paths are there?

Above is a 3 x 7 grid. How many possible unique paths are there?

Note: m and n will be at most 100.

  int uniquePaths(int m, int n) {    
   if(m <= 0 || n <= 0 )
    return 0;

   int paths[100][100];
   paths[0][0] = 1;

   for(int i = 1; i < n; i++)
   {
    paths[0][i] = 1;
   }

   for(int j = 1; j < m; j++)
   {
    paths[j][0] = 1;
   }


   for(int i = 1; i < m ; i++)
   {
    for(int j = 1  ; j < n ; j++)
    {
     paths[i][j]  = paths[i-1][j] + paths[i][j-1];
    }
   }


   return paths[m-1][n-1];
    }