def diagonal_sum(matrix, n): # 主对角线之和 main_diagonal_sum = sum(matrix[i][i] for i in range(n)) # 次对角线之和 secondary_diagonal_sum = sum(matrix[i][n-i-1] for i in range(n)) # 总和 total_sum = main_diagonal_sum + secondary_diagonal_sum return total_sum # 输入矩阵 n = int(input("请输入矩阵的大小 n（N < 10）: ")) matrix = [] print("请输入矩阵的元素，按行输入：") 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( result)