C language

1. If a four-digit number is given as input through the keyboard, write a program to reverse the number. For example, if the number that is input is 1234 then the output should be displayed as 4321. [Hint: make use of mod (%), division (/) and multiplication (*) operators.] [ 4 Points ] 2. C program to swap two numbers without using a third variable. [ 2 Points ] 3. Write a C Program without the main () function. Explain the technique which you used and read about it. (Use C comments at the beginning of the program to explain the chnique) [ 4 Points ]