3. Write the complete function definition for halfpyramid Notes: 1) In the function body, do NOT use a counter to tally the number of characters printed. Instead, use this formula to sum the first n positive integers: n (n+1)/2. 2) In your fprintf statement, use %c (the format specifier for one character). 3) Comments are NOT required Here are two sample function calls: Here is the corresponding output produced by halfpyramid: halfpyramid (5, '*')* There are 15 characters in this design halfpyramid (3,'Y')Y There are 6 characters in this design