T his article is about easiest way to perform read and write operation from file. File handling is one of the most important aspect of programming and it becomes more important when we do competitive programming. Here are some context when you need to deal with files in comptetive programming. 1) Some specific programming contests like Google Code Jam and Facebook Hacker Cup they provide a file for input. You have to read input from that file and write answers into a file and upload on server within limited time. 2) If you are trying to code for a problem. Suppose the problem was that a square matrix is given and you have to rotate the matrix by 90 degree clock-wise. First line of input indicate the total no. of test cases and first line before matrix represents size of matrix. Then input would be like this. 3 5 10 23 43 34 21 11 13 43 30 71 10 23 43 ...