def diagonal_sum(matrix, n): main_diagonal_sum = 0 secondary_diagonal_sum = 0 for i in range(n): main_diagonal_sum += matrix[i][i] secondary_diagonal_sum += matrix[i][n-i-1] # 如果n是偶数，中间的元素被重复计算了一次，需要减去 if n % 2 == 0: secondary_diagonal_sum -= matrix[n//2][n//2] return main_diagonal_sum + secondary_diagonal_sum # 输入矩阵 n = int(input("请输入矩阵的大小N（N<10）：")) matrix = [] for _ in range(n): row = list(map(int, input().split())) matrix.append(row) # 计算对角线之和 result = diagonal_sum(matrix, n) print("对角线之和是：", result)