* 1. Open the file with the name 'folderPath', which is a folder * 2. get the list of all files in the folder with built-in method .list() * 3. Create a string named fileSeparatorChar with method System. getProperty("file. separator"), for the separator is different based on OS * 4. Iteratively explore every file with in the file list in step 2 * 4.1 If the file does not end with '.txt', ignore it * 4.2 Count the number of positive files or negative files * 4.3 Classify the file with method classifyReview. The input should be the full path of the file (folderPath + fileSeparatorChar + fileName) * 4.4 Count the number of correctly/not correctly classified file * 4.5 Output following information: Full path and name of the file, ground truth, and classification result