A compiler is used to convert a program written in some high language into a target machine understandable language. This conversion is done in one step and reports all the errors of the program at the end. In case an error(s) is found, it is rectified and recompiled. Interestingly, the program compilation process continues till the last statement of the program and after that all the errors are removed (or repaired). It is very important to notify that compilers are large programs which reside permanently on secondary storage and when translation of program is to be done, they are copied into the main memory of computer. The programmer can copy the executable object code onto any other similar machine and run the program without compiling it again.