Write a C program to perform the above data

Quote:

i tried using the concept of if else

That's a start.
Now you should try using also structs, arrays, and the switch statement.

Some general code examples for you to see and examine.
https://en.wikipedia.org/wiki/Conditional_%28computer_programming%29
http://www.awitness.org/delphi_pascal_tutorial/c++_delphi/c++_if_then_else.html
https://www.siteforinfotech.com/2014/07/program-in-c-to-sort-list-ascending-order.html
https://www.thoughtco.com/the-if-then-and-if-then-else-statements-2033884


I would suggest to approach this by first writing a list on paper of what I want the user to see.

dosas        /   cost (Rs or RS)
             /   Plain   /   Onion   /   small   /   medium   / large
Plain Dosa   /   15      /   25 

etcetera

Then write out manually the if then else conditions.

Program this a little at a time.

Then use a simple program that does not do much other than say "hello world".

Then add to the hello world program a simple if then action.

Then add to the hello world program an else into it.

Then go back and add in more of the if's and the then's and the else's.

Very important for beginners:
Test compiling and running the code often. Do not write a lot of code between tests, just enough for it to work a little more.

Get this to work for all of the conditions before you start on the "If the dosa is to be collected then the order requires only name to be valid." part.

Then you might be ready to ask about the next part.

It can all be done with if then else. All of it. You do not need to even look at structs or arrays or switches until you have the if then else working. Then if you want to get into structs or arrays or switches you can, but they are not necessary for learning basic conditional logic. You can write the entire program without them.

Ask more later somewhere after you get the if then else working.

C is not difficult.

Take your time and you can do this.