求大神指导，这段代码怎么添加判断条件。就是不满足这个条件的输出另外的结果

double min = Euc_dist[0];
int label;
for (i=0;i {
if (min>=Euc_dist[i])
{
min = Euc_dist[i];
label = i;
}}

printf("%d.jpg is mathcing!",label+1);

double min = Euc_dist[0];
int label = -1;
for (i=0;i {
if (min>=Euc_dist[i])
{
min = Euc_dist[i];
label = i;
}}
if (label == -1)
printf("nothing matched");
else
printf("%d.jpg is matching!",label+1);

点这里编辑框上第六个图标，把代码放在里面，以免丢失字符。

直接把代码贴在这里，说清楚需求就可以了。

// face_recognition.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include "Process.h"
#include "My_Matrix.h"

int _tmain(int argc, _TCHAR* argv[])
{
double *T,*L,*m,*b,*q,*c,*p_q,*projected_train,*T_test,*projected_test,*eigenvector,*Euc_dist;
double eps,temp;
int i,j,flag,iteration,num_q;
char res[20];
IplImage *tmp_img,*test_img;

T = (double *)malloc(sizeof(double)*IMG_HEIGHT*IMG_WIDTH*TRAIN_NUM);    //原始数据
T_test = (double *)malloc(sizeof(double)*IMG_HEIGHT*IMG_WIDTH*1);       //测试数据
m = (double *)malloc(sizeof(double)*IMG_HEIGHT*IMG_WIDTH);      //平均值
L = (double *)malloc(sizeof(double)*TRAIN_NUM*TRAIN_NUM);       //L=T'*T，协方差矩阵
b = (double *)malloc(sizeof(double)*TRAIN_NUM);             //L的特征值
q = (double *)malloc(sizeof(double)*TRAIN_NUM*TRAIN_NUM);   //L特征值对应的特征向量
c = (double *)malloc(sizeof(double)*TRAIN_NUM);             //实对称三对角矩阵的次对角线元素

eps = 0.000001;
memset(L,0,sizeof(double)*TRAIN_NUM*TRAIN_NUM);

//存储图像数据到T矩阵
for (i=1;i<=TRAIN_NUM;i++)
{
    sprintf(res,".\\TrainDatabase\\%d.jpg",i);
    tmp_img = cvLoadImage(res,CV_LOAD_IMAGE_GRAYSCALE);
    load_data(T,tmp_img,i);
}

//求T矩阵行的平均值
calc_mean(T,m);

//构造协方差矩阵
calc_covariance_matrix(T,L,m);

//求L的特征值，特征向量
iteration = 60;
cstrq(L,TRAIN_NUM,q,b,c);
flag = csstq(TRAIN_NUM,b,c,q,eps,iteration); //数组q中第j列为数组b中第j个特征值对应的特征向量
if (flag<0)
{
    printf("fucking failed!\n");
}else
{
    printf("success to get eigen value and vector\n");
}

//对L挑选合适的特征值，过滤特征向量
num_q=0;
for (i=0;i<TRAIN_NUM;i++)
{
    if (b[i]>1)
    {
        num_q++;
    }
}
p_q = (double *)malloc(sizeof(double)*TRAIN_NUM*TRAIN_NUM);         //挑选后的L的特征向量，仅过滤，未排序
projected_train = (double *)malloc(sizeof(double)*TRAIN_NUM*num_q); //投影后的训练样本特征空间
eigenvector = (double *)malloc(sizeof(double)*IMG_HEIGHT*IMG_WIDTH*num_q);//Pe=λe,Q(Xe)=λ(Xe)，投影变换向量
pick_eignevalue(b,q,p_q,num_q);
get_eigenface(p_q,T,num_q,projected_train,eigenvector);

//读取测试图像
test_img = cvLoadImage(".\\TestDatabase\\4.jpg",CV_LOAD_IMAGE_GRAYSCALE);
projected_test = (double *)malloc(sizeof(double)*num_q*1);//在特征空间投影后的测试样本
for (i=0;i<IMG_HEIGHT;i++)
{
    for (j=0;j<IMG_WIDTH;j++)
    {
        T_test[i*IMG_WIDTH+j] = (double)(unsigned char)test_img->imageData[i*IMG_WIDTH+j] - m[i*IMG_WIDTH+j];
    }
}

//将待测数据投影到特征空间
memset(projected_test,0,sizeof(double)*num_q);
matrix_mutil(projected_test,eigenvector,T_test,num_q,IMG_WIDTH*IMG_HEIGHT,1);

//计算projected_test与projected_train中每个向量的欧氏距离
Euc_dist = (double *)malloc(sizeof(double)*TRAIN_NUM);
for (i=0;i<TRAIN_NUM;i++)
{
    temp = 0;
    for (j=0;j<num_q;j++)
    {
        temp = temp + (projected_test[j]-projected_train[j*TRAIN_NUM+i])*(projected_test[j]-projected_train[j*TRAIN_NUM+i]);
    }
    Euc_dist[i] = temp;
    //printf("%f \n",temp);
}
//寻找最小距离
double min = Euc_dist[0];
int label;
for (i=0;i<TRAIN_NUM;i++)
{
    if (min>=Euc_dist[i])
    {
        min = Euc_dist[i];
        label = i;
    }
}
printf("%d.jpg is mathcing!",label+1);
return 0;

}

这个代码是根据测试集与训练集投影向量之间的距离做排序，挑距离最小的作为匹配项。既然是找最小值，那么min的初始值默认为第一组距离。可以再增加个判断条件，就是当找到的最小值，仍大于某个阈值时，打印匹配失败。