(1).how do a program run:(example hellp.c)
four parts:pre-processor(.i .text)->compiler(.s text)->assembler(.o binary)->Linker(.exe binary)
1.pre-processor:add the head file to hello.c;
2.compiler:translate high-level language(c++ or c ==)to low-level language(assembly language);
3.assemble:translate assembly language to binary file(manchine language ) manchine instruction;
4.Linker:the linker handles merging the c library and hello.c(merging printf.o and hello.o to hello file) to executable object program,
then be loaded into memory and executed by the system.