Write checkWin function

src/main/c/VierGewinnt.c

@@ -215,6 +215,15 @@ int checkDiagonalRL(char board[ROWS][COLS], char player) {
         }
     }
     return 0;
+
+}
+
+// Write checkWin function
+int checkWin(char board[ROWS][COLS], char player) {
+    return checkHorizontal(board, player) ||
+           checkVertical(board, player) ||
+           checkDiagonalLR(board, player) ||
+           checkDiagonalRL(board, player);
 }