首先画出k_means算法的流程图：
具体代码，C++实现：
#include <iostream>
#include <fstream>
#include <cmath>
#include <ctime>
using namespace std; const int N = ; typedef struct {
double x1,x2;
int flag;
}oneNode; oneNode node[N];
int k,n; void DataInput();
void SetInitial(oneNode *p,oneNode *q);
void SetQzero(oneNode &qi);
bool GetExist(int xm,int *sb,int i);
void DataIteration(oneNode *p,oneNode *q,double &E1,double &E3);
double GetRange(oneNode &node1,oneNode &node2);
bool JudgeCondition(oneNode *p,oneNode *q);
void DataOutput(oneNode *p,double E1,double E3); int main(){
int E2=;
double E1 = ,E3;
n = ; DataInput(); //将txt文件中记录读入，存储到oneNode列表中 cout<<"请输入新的聚类数目：";
cin>>k;
oneNode *p = new oneNode[k];
oneNode *q = new oneNode[k]; SetInitial(p,q); //初始化开始的k个聚类中心 DataIteration(p,q,E1,E3); //循环处理每条记录，获得新的聚类中心 DataOutput(p,E1,E3); //输出程序运行结果 delete[] q;
delete[] p;
return ;
} void DataInput(){
ifstream ifs; //通过txt文件，读入所有记录,将记录存储到oneNode列表中
ifs.open("D:\k_means\\aa11.txt");
if (!ifs.is_open())
{
cout<<"文件读取失败"<<endl;
exit();
} while (!ifs.eof()) //将txt文件中记录，存储到node[]中
{
ifs>>node[n].x1;
ifs>>node[n].x2;
n++;
}
} void SetInitial(oneNode *p,oneNode *q){
int xm;
int *sb = new int[k];
srand((unsigned)time());
for (int i = ;i < k;i++)
{
do
{
xm = rand()%n;
} while (GetExist(xm,sb,i));
sb[i] = xm; p[i] = node[xm]; SetQzero(q[i]);
}
delete[] sb;
} void SetQzero(oneNode &qi){
qi.x1 = ;
qi.x2 = ;
qi.flag = ;
} bool GetExist(int xm,int *sb,int i){
bool b = false;
for (int j = ;j < i;j++)
{
if (sb[j] == xm)
{
b = true;
break;
}
}
return b;
} void DataIteration(oneNode *p,oneNode *q,double &E1,double &E3){
int i,j,E2 = ;
bool b;
do
{
E3 = ;
for(i = ;i < n;i++){
double mm = GetRange(node[i],p[]);
int m = ;
for (j = ;j < k;j++)
{
double nn = GetRange(node[i],p[j]);
if (mm > nn)
{
mm = nn;
m = j;
}
}
node[i].flag = m;
E3 += GetRange(node[i],p[m]);
q[m].x1 += node[i].x1;
q[m].x2 += node[i].x2;
q[m].flag += ;
}
if (E2 == )
{
E1 = E3;
}else if(E2 > ){
if (E1 <= E3)
{
break;
}else{
E1 = E3;
}
}
E2++;
for (i = ;i < k;i++)
{
if (q[i].flag != )
{
q[i].x1 = q[i].x1/q[i].flag;
q[i].x2 = q[i].x2/q[i].flag;
}
}
b = JudgeCondition(p,q);
for (i = ;i < k;i++)
{
p[i] = q[i]; SetQzero(q[i]);
}
} while (b); } double GetRange(oneNode &node1,oneNode &node2){
return pow(node1.x1-node2.x1,)+pow(node1.x2-node2.x2,);
} bool JudgeCondition(oneNode *p,oneNode *q){
bool bo = false;
for (int i = ;i < k;i++)
{
if (pow(p[i].x1-q[i].x1,)+pow(p[i].x2-q[i].x2,) >= 5.0)
{
bo = true;
break;
} }
return bo;
} void DataOutput(oneNode *p,double E1,double E3){
if (E1 != E3){
cout<<"操作失败"<<endl;
}else{
cout<<"本次总体误差是："<<E1<<endl;
ofstream ofile("D://k_means/aa11result.txt");
for (int i = ;i < k;i++)
{
ofile<<"第"<<i+<<"个聚类中心是："<<"("<<p[i].x1<<","<<p[i].x2<<")"<<endl<<"属于第"<<i+<<"个聚类的所有点是："<<endl;
for (int j = ;j < n;j++)
{
if (node[j].flag == i)
{
ofile<<node[j].x1<<" "<<node[j].x2<<endl;
}
}
} }
}