C language rounding

/ * Make two decimal places in h and round the third digit. 
If h is 1234.567, the function returns 123.570000 
h is 123.564, then it returns 123.560000 * / 
#include <stdio.h> 
#include <conio.h> 
# include <stdlib.h> float fun ( float h) 
{ int temp = ( int ) (h * 1000 + 5 ) / 10 ;
     return ( float ) temp / 100.0 ; 
} void main () 
{ float a;
     while (scanf ( " % f " , & a)! = 
    {


    

     EOF)
        printf("%f\n",fun(a));
    }
}

Rounding algorithm: if you want to be accurate to the nth digit after the decimal point, you need to perform operations on n + 1 digits.
The method is to multiply the decimal by 10 to the power of n + 1 and add 5, then divide by 10 and force to convert to an integer,
then divide the number by 10 to the power of n and force to convert to floating point.