C Program, Document everyline please

Write a program as follows. Define and initialize a variable of type integer. Then, compute and print the sum of first and last digit. For example, if the number is 5492, the sum would be 2+5=7. You are not allowed to change the data type of the variable or assign it to another variable of another data type. Note that the solutions should work for any integer number, i.e., solution is not dependent on the number of digits