C语言实现knn

 以后写代码一定要谨慎，提高代码的正确率。 

/***************************************
 * 1.初始化距离为最大值
 * 2.计算未知样本和每个训练样本的距离为dist
 * 3.得到目前k个最邻近样本中的最大距离maxdist
 * 4.如果dist小于maxdist，则将改训练样本作为k-最近邻样本
 * 5.重复2、3、4，直至未知样本和训练样本的距离都算完
 * 6.统计k个最近邻样本中每个类别出现的次数
 * 7.选择出现频率最大的类别作为未知样本的类别
 * *****************************************/

#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>
#define MAX 0x7fffffff
#define K 3

double  cal_dist(int n,double *x,double *y)
{
    double sum = 0.0;
    int i =0;
    for(i=0;i<n;i++)
    {
        sum += pow((x[i]-y[i]),2.0);
    }
    return sqrt(sum);
}

void bubbleSort(double **array,int count,int flag)
{
    int i = count,j;
    double temp;
    while(i>0)
    {
        for(j=0;j<i-1;j++)
        {
            if(flag == 0)
            {
                if(array[0][j] > array[0][j+1])
                {
                    temp = array[0][j];
                    array[0][j] = array[0][j+1];
                    array[0][j+1] = temp;
                    temp = array[1][j];
                    array[1][j] = array[1][j+1];
                    array[1][j+1] = temp;
                }

            }
            else if(flag == 1)
            {
                if(array[1][j] > array[1][j+1])
                {
                    temp = array[1][j];
                    array[1][j] = array[1][j+1];
                    array[1][j+1] = temp;
                    temp = array[0][j];
                    array[0][j] = array[0][j+1];
                    array[0][j+1] = temp;
                }
            }
        }
        i--;
    }
    return;
}
int main()
{
    int n,m;
    FILE *fp;
    fp = fopen("/data.txt","r");
    fscanf(fp,"N=%d,D=%d",&n,&m);
    printf("N=%d,D=%d
",n,m);
    double  **array;
    array = (double **)malloc(n*sizeof(double));
    array[0] = (double *)malloc(n*m*sizeof(double));
    int h,j = 0,i =0;
    for(i=1;i<n;i++)
    {
        array[i] = array[i-1] + m;                            
    }
    for(i=0;i<n;i++)
    {
        for(j=0;j<m;j++)
        {
            fscanf(fp,"%lf",&array[i][j]);                                            
        }                                
    }
    double **temp;
    temp = (double **)malloc(2*sizeof(double));
    temp[0] = (double *)malloc(2*K*sizeof(double));
    for(i=1;i<2;i++)
    {
        temp[i] = temp[i-1] + K;
    }
    for(i=0;i<2;i++)
    {
        for(j=0;j<K;j++)
        {
            temp[i][j] = MAX*0.1;
        }
    }
    double *testdata;
    double max_dist = 0.0;
    double distance = 0.0;
    double tmp = 0.0;
    testdata=(double *)malloc((m-1)*sizeof(double));
    printf("input test data containing %d numbers:
",m-1);
    for(i=0;i<(m-1);i++)
    {
            fscanf(fp,"%lf",&testdata[i]);
    }
    close(fp);
    while(1)
    {
        for(i=0;i<K;i++)
        {
            if(K > n) break;
            temp[0][i] = cal_dist(n,testdata,array[i]);
            temp[1][i] = array[i][m-1];
        }
        for(i=0;i<K;i++)
        {
            printf("%4lf,%4lf
",temp[0][i],temp[1][i]);
        }
        printf("
");
        bubbleSort(temp,K,0);
        max_dist = temp[0][K-1];
        for(i=K;i<n;i++)
        {
            distance = cal_dist(n,testdata,array[i]);
            if(max_dist > distance)
            {
                for(j=0;j<K;j++)
                {
                    if(distance < temp[0][j])
                    {
                        for(h=K-1;h>j;h--)
                        {
                            temp[0][h] = temp[0][h-1];
                            temp[1][h] = temp[1][h-1];
                        }
                    }
                    temp[0][j] = distance;
                    temp[1][j] = array[i][m-1];
                }
            }
            max_dist = temp[0][K-1];
        }
        bubbleSort(temp,K,1);
        break;
    }


    int value_label = 0;
    int count = 0;
    int flag = 0;
    for(i=0;i<K-1;i++)
    {
        if(temp[1][i] != temp[1][i+1])
        {
            if(flag > count)
            {
                flag = count;
                value_label = temp[1][i];
                count =1;
            }
        }
        else
        {
            count ++;
        }
    }
    if(count > flag)
    {
        value_label = temp[1][K-1];
        flag = count;
    }
    printf("Predict message is %d
",value_label);
    return 0;
}