All HLL statements must be converted to machine code in order for a processor to run them. The source code program is run through a program called an interpreter . Each line of the program is sent to the interpreter which converts it into equivalent machine code instructions which are then executed. The next source line is then fetched from memory, converted and executed. This process is repeated till the entire program has been executed.
Compilers generate code which is reasonably fast.
The source program is written using a text editor. Most compiled languages do not use line numbers. Once the program has been written using the appropriate source statements, it is then passed to a compiler which converts the entire program into object code. Normally, the object code cannot be run on the computer system, so the object code file is then sent to the linker which creates an executable program. Because the entire program is converted to machine code, it runs very quickly.