KNN算法C++实现

KNN算法C++实现。C++11

/* ***********************************************
Author        :guanjun
Created Time  :2016/6/20 18:22:32
File Name     :1.cpp
************************************************ */
#include <iostream>
#include <cstring>
#include <cstdlib>
#include <stdio.h>
#include <algorithm>
#include <map>
#include <string>
#include <math.h>
#include <stdlib.h>
#include <fstream>
#define maxn 10010
using namespace std;

int k;
struct node{
    double x1,x2,x3,x4,x5;
    string s;
}nod[maxn];
pair<double,string>p[maxn];
map<string,int>mp;

ifstream fin;
int input(string s){
    fin.open(s);
    if(!fin){
        cout<<"can not open the file "<<s<<endl;
        exit(1);
    }
    int i=1;
    while(fin>>nod[i].x1>>nod[i].x2>>nod[i].x3>>nod[i].x4>>nod[i].x5>>nod[i].s){
        nod[i].x1*=100.0;nod[i].x2*=100.0;nod[i].x3*=100.0;nod[i].x4*=100.0;nod[i].x5*=100.0;
        i++;
    }
    return i;
}
double mul(double x,double y){
    return (x-y)*(x-y);
}
double dis(node a,node b){
    double tmp=mul(a.x1,b.x1)+mul(a.x2,b.x2)+mul(a.x3,b.x3)+mul(a.x4,b.x4)+mul(a.x5,b.x5);
    return<