After writing the programme it is saved with .c name. During its execution code file gets converted into executable in four different steps.Firstly c code is preprocessed and get converted into .i file. Then .i file is compiled and get converted into .s file. This .s file is assembled and converted into .o file which is our object code. Finally linker convert the .o file into .c file , then loader loads all the executable files with it and our output as ./a.out is generated.