c programming

What is wrong with the factorial program in the image below??

ig there are two mistakes
1st a-- should be below to b*=a
2nd for what that printf is there remove it and does that question have testcases?

First, remove Line 5. You cannot print anything out of format.
Second, problem FCTRL2 contains test cases, t<=100.
Last, as per constraints you have to find factorial for n<=100. So, expected logic is to multiply two numbers in string form.

Thank you for the suggestion …

Thank you for the suggestion…