Question

Write a code snippet (segment not a whole program) that sums the values at the corners of an X by Y 2-dimensional array.

Answer 1

// Let the 2d array be A[x][y]

// A 2d array will have 4 corners

int sum=A[0][0]+A[0][y-1]+A[x-1][0]+A[x-1][y-1];

/*

if A = 1 2 3

4 5 6

so, A[0][0] = 1

A[0][y-1] = 3

A[x-1][0] = 4

A[x-1][y-1] = 6

sum = 1+3+4+6=14

Corner values are now summed

*/

return sum; // sum is returned if any function is calling it

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if you want to just print the sum of elements of each column then the following snippet should help

int sum;

   for(i=0;i<y;++i)
   {sum=0;
   for(j=0;j<x;++j)
   {
   sum+=A[j][i]; // sum = old sum + A[j][j]
   }
   cout<<"Sum of "<<i+1<<"th column : "<<sum<<"\n";
   }