vector类，文件读写的基本操作。具体是随机产生两百个数，分别以vector的形式写入.txt文件中，然后打开两个文件，读出数，计算两个vector的乘积，并把结果写入.txt中。-vector type, the document read and write basic operation. Concrete is randomly generated number 200, respectively, the form of vector write. Txt file, and then open the two documents, read out the number of calculated two vector product, and write the results. Txt in.