How do I save user input for 2d array

Question

i have 5 sets of data

int a[] = { 18080, 18961, 18985, 18761, 17821, 19021, 18452, 20000 };
int b[] = { 4922, 4904, 4993, 5076, 4970, 4900, 4718, 4757 };
int c[] = { 13898, 14424, 14290, 14362, 12623, 13139, 13775, 15081 };
int d[] = { 7382, 7323, 7304, 7675, 7147, 7335, 6972, 7740 };
int e[] = { 1398, 1438, 1414, 1435, 1361, 1420, 1450, 1476 };
how do i store user input using 2D array
to minus of the quarterly average of all sectors.

This is my question differences between average GDP of all sectors and GDP of individual sector for a
selected quarter and year.