求5*5矩阵主、副对角线元素之和及周边元素之和。编写主函数和函数replace()。主函数进行输入、输出和函数调用，replace()的功能是将一字符串中的某个字符替换成另一字符。-The sum of the main and the diagonal elements of the 5* 5 matrix and the sum of the surrounding elements. Write the main function and the function replace ().