在最小生成树中 怎么只输出了一个小环的节点，为什么？

#include<stdio.h>
#include<stdlib.h>
#define MAX 100
#define MAXCOST 9999
typedef struct vertex
{
    int num;
    int weight;
} vertex;
typedef struct
{
    vertex vers[MAX+1];
    int edges[MAX+1][MAX+1];
    int n,e;
} MGraph;
typedef struct
{
    int fromvex,endvex;
    int weight;
} Edge,Edgeset[MAX+1];
Edgeset GE;

void Creat(MGraph *g,int n,int e)
{
    int i,j,k,v1,v2;
    g->n=n;
    g->e=e;
    for(i=1; i<=g->n; i++)
        g->vers[i].num=i;
    for(i=1; i<=g->n; i++)
    for(j=1; j<=g->n; j++)
        g->edges[i][j]=0;
    printf("\n请输入权值 and 所对应的两条边的节点的下标：\n") ;
    for(k=1; k<=g->e; k++)
    {

        scanf("%d",&g->vers[k].weight);
        scanf("%d%d",&v1,&v2);
        g->edges[v1][v2]=g->vers[k].weight;
        g->edges[v2][v1]=g->vers[k].weight;
    }
}

void Prim(MGraph *g)
{
    int i,j,k,mincost;
    int lowcost[MAX+1];
    int closevertex[MAX+1];
    for(i=1; i<=g->n; i++)
    {
        if(i==1)
            lowcost[i]=0;
        else
            lowcost[i]=g->edges[1][i];
        closevertex[i]=1;
    }
    for(i=1; i<g->n; i++)
    {
        mincost=MAXCOST;
        k=1;
        for(j=2; j<=g->n; j++)
            if(lowcost[j]!=0&&lowcost[j]<mincost)
            {
                mincost=lowcost[j];
                k=j;
            }
        if(mincost==MAXCOST)
        {
            printf("图不连通，无生成树！");
            return ;
        }
        printf("(%d,%d,%d)\n",closevertex[k],k,lowcost[k]);
        lowcost[k]=0;
        for(j=1; j<=g->n; j++)
        {
            if(lowcost[j]!=0&&g->edges[k][j]<lowcost[j])
            {
                closevertex[j]=k;
                lowcost[j]=g->edges[k][j];
            }
        }
    }
}

/*

void CreatGE(MGraph *g,Edgeset GE)
{
    int i,j;
    Edge temp;
    int k=1;
    for(i=1; i<=g->n; i++)
        for(j=1; j<i; j++)
            if(g->edges[i][j]!=MAXCOST)
            {
                GE[k].weight=g->edges[i][j];
                GE[k].fromvex=i;
                GE[k].endvex=j;
                k++;
            }
    for(i=1; i<=g->e; i++)
        for(j=1; j<g->e; j++)
            if(GE[j].weight>GE[j+1].weight)
            {
                temp=GE[j];
                GE[j]=GE[j+1];
                GE[j+1]=temp;
            }

}
void Kruskal(MGraph g,Edgeset GE,Edgeset TE)
{
    int vest[MAX],i,j,k,d,m1,m2;
    for(i=1;i<=g.n;i++)
        vest[i]=i;
    for(d=1,k=1;k<g.n;i++)
    {
        m1=vest[GE[d].fromvex];
        m2=vest[GE[d].endvex];
        if(m1!=m2)
        {
            TE[k]=GE[d];
            k++;
            for(j=1;j<=g.n;j++)
            {
                if(vest[j]=m2)
                    vest[j]=m1;
            }
        }
    }
}

*/
int main()
{
    MGraph *g;
    int n,e;
    g=(MGraph*)malloc(sizeof(MGraph));
    printf("请输入顶点数和边数:");
    scanf("%d%d",&n,&e);
    Creat(g,n,e);
    Prim(g);
    return 0;


}