Change number of digits after comma depending on the situation

Question

I know I can get a limit of digits after the comma with %.2f for float and %.2lf for double.

How can I change this limit depending on the occasion?

For example:

Get a two-digit limit with float that would be %.2f, that is, if the number is 310.22, the same will appear - but, if the number ends at zero, decrease this limit: in the case of 310.10, would be 310.1 (and the numbers will vary).

When compiling the programming below with 16 and 455 the result will be 436.10, but I want to show you how 436.1, without modifying the other results which, if they do not end with zero, have two decimal places.

#include<stdio.h>

int main()
{
    double d,km,km2,v,k;
    scanf("%lf%lf",&d,&km);
    v=d*30;
    km2=km*0.01;
    v=v+km2;
    k=v*0.10;
    v=v-k;
    printf("\n%.2lf",v);
    return 0;
}

Answer 1

You have to use the %g. Behold all possible formatting.

#include <stdio.h>

int main(void) {
    printf("%g\n", 310.0);
    printf("%g\n", 310.1);
    printf("%g\n", 310.12);
}

Behold working in the ideone. And in the repl it.. Also put on the Github for future reference.