Calculating Sum of diagonals in matrix

/*
		Humza Khawar 
		Finding Sum of Right Diagonals

*/
#include<stdio.h>

void main()
{
		
	//initialization of array
	int matrix[10][10] = { 0 },size,sum_of_diagonals=0;
	//inputing size
	printf("\n Enter he size of the Square Matrix: ");
	scanf("%d",&size);
	//inputing elements of matrix

		for (int i = 0; i < size; i++)
		{
				for (int j = 0; j < size; j++)
				{
					printf("\nEnter Number [%d] [%d]: ", i, j);
					scanf("%d", &matrix[i][j]);
				}
		}
	//printing the matrix
	printf("\nYour Matrix\n");

		for (int i = 0; i < size; i++)
		{
			printf("\n |");
			for (int j = 0; j < size; j++)
			{
				printf(" %3d ", matrix[i][j]);
			}
			printf(" |");
		}
	//taking sum or right diagonals
		for (int i = 0; i < size; i++)
		{
			for (int j = 0; j < size; j++)
			{
				if ((i + j +2) == (size + 1)) {
					sum_of_diagonals += matrix[i][j];
				}

			}

		}
		//printing sum
		printf("\n\n Sum of Right Diagonal = %d\n\n", sum_of_diagonals);
}