%3.2 what actually it's mean?

Answer 1

%3.2f => outputs atleast 3 Integer digits and value rounded upto 2 decimal points..
Ex:
N = 4.78899
printf("%3.2f",N);
Output is :
4.79
(2 empty spaces before 4)
To see it accurately, check this
printf("%03.2", N);
outputs : 004.79

Edit:
See this
https://www.sololearn.com/learn/C/2914/

Answer 2

You are telling there are 2empty space before 4.
Then why we are adding empty space?

Answer 3

For example, to make table form, it helps
Like
Name id. Marks
Aaa 1. 90
...
In this kind of farmating, that helps..