The precision of float floating point number can be guaranteed within 6 decimal places, so your problem is not the precision of float, because you don't know what your wrong result is and you can't guess it.
The following is a program that uses arrays and loops, which saves code and adds two kinds of security processing: double precision and security operation (this also applies to your program, you can modify it).
# include & ltstdio.h & gt
# include & ltstdlib.h & gt
int？ Master ()
{
Double? x； //Double precision
int？ Y, me;
int？ a[ 13]={ 10000，5000，2000， 1000，50，20， 10，5，2， 1 }；
int？ b[ 13]；
scanf("%lf "，& ampx)；
x=？ x * 100.0；
y =(int)x； //Safety calculation
For what? (I = 0； I< 13; i++)
{
b[i]？ =? y/a[I]；
y？ =? y % a[I]； //y？ -? a[i]*b[i]
}
For what? (I = 0； I< 13; i++)
{
if(b[i]==0)？ Continue;
if(a[I]& lt； 10)// min
printf("%d？ Finn:? %d\n "，a[i]，b[I])；
Or what? if(a[I]& lt； 100)// coke
printf("%d？ Jiao:? %d\n "，a[i]/ 10，b[I])；
Or what? //yuan
printf("%d？ Yuan:? %d\n "，a[i]/ 100，b[I])；
}
System ("suspended");
Return? 0;
}