Added a Cprogram to check primality

[Pulgit555]

I have added a Cprogram to check whether a no. is prime or not.
I have used math.h library and used sqrt predefined function and break condition to reduce the time complexity of the code to run.

[gouravthakur39]

@Pulkit555

1. Users should know what to enter.
2. Remove extra binary file

[Pulgit555]

I have made the changes according to you.
please check and verify me.

[gouravthakur39]

@Pulkit555 Result is always "Yes". Please fix it.

[gouravthakur39]

@Pulkit555 Also, the binary file is still there. please remove it. You need to exclude it while committing.
Instructions for git in case you don't know:

1. git status - Tells what file changed
2. git add filename - files to be added for commit.
   You need to do git add swappingwithoutthirdvariable.cand then
3. git commit -m "your commit message"
   Obviously, I am assuming things here.

[gouravthakur39]

@Pulkit555 The binary file is still there.

[Pulgit555]

Thanks for merging my file .How could I contribute further?