 Hello friends, I am Sanjay Gupta. In this video, I am going to demonstrate you the use of hashif, hashelse, and hash and def preprocessor directive for conditional compilation in C programming. Before starting, you can note how you can search my youtube channel. You can type my name Sanjay Gupta in youtube. My channel will be available there. You can watch various programming related videos here. Now I am going to demonstrate you the use of hashif, hashelse, and hash and def. First of all, I am going to include a header file that is stdio.h. Now I am going to define a macro whose name is ace and suppose its replacement value is 20. So in the program, whenever I will be using identifier ace, it will be replaced automatically with 20. Now I am going to use first preprocessor directive that is hashif ace w equals to 20. So hashif preprocessor directive checks a value of a macro with a particular constant value if they are matching or the condition is true. Then a particular set of block will be executed. So here I can print the masses. Ace is equals to 20. Then hashelse, I can print masses. Ace is not equals to 20. Now to close this hashif, hashelse, I have to use hash and def and then return 0. So this way I have implemented the use of hashif for checking the value of macro. Now I am going to execute this code so that you can see whether it is working properly or not. So you can see the output. It is showing ace is equals to 20. So it is working properly. Now I am going to convert it like this. Ace greater than equals to 18. If it is true, then it will print eligible for vote. So in India, if you are equals to or greater than 18 years, then you are eligible for vote. Otherwise not eligible for vote. So right now preprocessor hash define is defining a macro name is ace and its replacement value is 20. So this if condition that is written with hashif will be true. So again I am going to execute this code so that you can see the output. It is showing eligible for vote. Now if ace is, ace replacement value is 15. Now let's see what happens now. Now this time you can see it is showing not eligible for vote. So it means both hashif and hashelse are working properly. Both are printing correct results on output screen as per the condition. So this way you can use hashif and hashelse for conditional compilation in C programming. If you want to watch more programming related videos, you can search my name Sanjay Gupta in YouTube. My channel will be available there. You can also download my programming app that is TechEmise which is available on Google Play. Thank you for watching this video.