Why the code didn't give the right answer?

Question

https://code.sololearn.com/cN2JR2qKO01H/?ref=app

I'm doing an exercise on run.codes in C language, where the inputs are 1.88 and M.
The output is supposed to be 78.676, but it is 78.674.

I'm new in programming and don't speak English very well, so sorry if I write something wrong.

Answer 1

If you check value 1.88 with
printf("%f\n", h);
before
w = (72.70 * h) - 58.00;
you will see 1.879974
I don't know why (if you check before scanf("%s", &g); you will see 1.880000). But with doubles no problem, so this code works:

#include <stdio.h>

int main()
{
double h, w;
char g;

scanf("%lf" ,&h);
scanf("%s" ,&g);

if(g=='M')
{
printf("%lf\n", h);

w = (72.70 * h);
printf("%.3lf", w);
}

else if(g=='F')
{
printf("%lf\n", h);

w = (62.10 * h) - 44.70;
printf("%.3lf", w);
}
}

May be it is because of memory layout of this variables after two scanf functions.

Answer 2

It has to with the precision of float. Double has 2x more precision than float.
https://www.google.de/amp/s/www.geeksforgeeks.org/difference-float-double-c-cpp/amp/