optimization in any programming language .

Hello friends , good morning to all readers , first why i choose this topic , i choose this topic because the term OPTIMIZATION used too much in raw-material of languages . 


Here i want to explain the basic thing or why it is used in languages and what is the thing behind it , that it is used too much in raw-material of language  . "optimization" is a term used with some different thinking , when you write any code and after compilation it is changed into machine understandable code . 


when any code changes into machine code , before it at intermediate level many optimization steps are taken . they are some-thing like that :- 


write a code :---- ( images from wiki-pedia )

int a = 30;
 int b = 9 - a / 5;
 int c;
  
 c = b * 4;
 if (c > 10) {
    c = c - 10;
 }
 return c * (60 / a);

after first optimization :--------

int a = 30;
 int b = 3;
 int c;
  
 c = 3 * 4;
 if (c > 10) {
    c = c - 10;
 }
 return c * 2;

after second optimization :-------

int c;
  
 c = 12;
 if (12 > 10) {
    c = 2;
 }
 return c * 2;

after third optimization :-------

return 4;

now in what basics these optimization steps are carried-out .
these steps are carried out in the basics of constant folding and constant propagation.


constant folding :- 
                             constant folding is a term which means that solving constant expression when they are needed .


constant propagation :- 
                                    constant propagation is term which means that passing you constant values with the help of some variable to some other expression .
                    int a = 10 ;
                    int z = 20 + a ;


at the compilation time , the value is passed to the expression is very accurately processed  , because if you process it with some false thinking than at the compilation it can create some problem , so optimization is very necessary in all languages .