浮点数取模

#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <set>
#include <map>
#include <vector>
#include <queue>
#include <algorithm>
#include <iostream>

using namespace std;

double a, d;
int n;

int main()
{
cin >> a >> d >> n;
int cnt = 0;
double len = 0;
for (int i = 1; i <= n; i++)
{
len += d;
int temp = len / a;
len = len - temp * a;
cnt += temp;
cnt %= 4;
if (cnt == 0)
{
printf("%.10lf %.10lf\n", len, 0.0);
}
else if (cnt == 1)
{
printf("%.10lf %.10lf\n", a, len);
}
else if (cnt == 2)
{
printf("%.10lf %.10lf\n", a - len, a);
}
else
{
printf("%.10lf %.10lf\n", 0.0, a - len);
}
}
return 0;
}

#include <cstdio>
#include <cmath>

using namespace std;

int main()
{
double a,d,x,y,s=0.0;
int n;
scanf("%lf%lf%d",&a,&d,&n);
for(int i=1; i<=n; i++)
{
s+=d;
s=fmod(s,4*a);
if(s <= a)x=s,y=0;
else if(s <=2*a)x=a,y=s-a;
else if(s <=3*a)x=a-(s-2*a),y=a;
else x=0,y=a-(s-3*a);
printf("%lf %lf\n",x,y);
}
return 0;
}