哎我偏不用

#include <bits/stdc++.h>
using namespace std;
double inx[5];
int main()
{
	cin>>inx[0];
	cin>>inx[1];
    cin>>inx[2];
    double maxn=-1;
    maxn=max(maxn,inx[0]);
    maxn=max(maxn,inx[1]);
    maxn=max(maxn,inx[2]);
    printf("%.3f\n%.3f",maxn,maxn);
	return 0;
}

C :

#include<stdio.h>
#define MAX(x,y) (x)>(y)? (x):(y)
double max(double x,double y,double z)
{
	double a;
	a=x>y?x:y;
	return(a>z?a:z);
}
int main()
{
	double a,b,c;
	scanf("%lf%lf%lf",&a,&b,&c);
	printf("%.3lf\n",max(a,b,c));
	printf("%.3lf\n",MAX(MAX(a,b),c));
	return 0;
}