请大佬指教哪里错了
#include <stdio.h>
int main()
{
int fn1(float time)
{
float money,km=12,time,oil=1,sum;
if(km<=3)
{
money=13+oil;
}
else if(0<=time<5||23<=time<=24)
{
money=13+2.3*1.2*(km-3)+oil;
}
else
{
money=13+oil+2.3*(km-3);
}
}
sum1=fn1(9);
sum2=fn(18);
printf("%f",sum1+sum2);
return 0;
}