C++ If else if statement Problems

i have a problem with the next question, i need to solve it by using if/else :

Write a program in which the user enters the coordinates of the black pawns (a, b) on the chessboard. The program must determine whether the pawn may move to get to one field (c, d): 1- in the ordinary move; 2- when it "hit" piece or pawn opponent. Note: Black pawn move on the board from the bottom up.

please any help?