蒟蒻求助

xdm我复制题解对照了下，感觉没啥区别但#2#3#4报错，有没有神犇解答一下，谢谢

#include<iostream>
#include<cstring>
#include<string>
#include<cmath>
#include<iomanip>
using namespace std;
int main(){
    int a,b,c=0,d=0;
    double c1=0,d1=0;
    cin>>a>>b;
    for(int i=b;i<=a;i+=b){
        c+=i;
    }
    d=(1+a)*a/2-c;
    printf("%.1lf %.1lf",(double)(c/(a/b)),(double)(d/(a-a/b)));
    return 0;
}