C :: Getting Correct Float Value Without Having To Write In Width / Precision

I have this

Code:
#include <stdio.h>
int main() {
float number1, number2;
printf("Enter two numbers separated by a comma ");
scanf("%f,%f", &number1, &number2);

[Code] ....

When it prints the values, it prints them as I want. the problem is, what happens when someone puts in values with different width and precision? Here I had to write in the width and precision to display the values that are specified in the book. but what happens when someone puts in something that doesn't have those width/precision?

I end up with a lot of zeros after the number. initially I got 24.000000 (zeros are not accurate amount) I needed to show just 24. (with the decimal)

So I included %2.0f which gave me 24 (without the decimal point) what if some one put in 24.556. I got 25 as a result.

Does the width mean how many numbers in total including the decimal point and that is a minimum?