graph *edge2;

edge2=(graph *)malloc(sizeof(graph)*e);

free(edge2);

这里free错了吗，为什么会出问题

应该是free（地址）；没错啊，郁闷那

void reform_map(graph *edge,int e)
{
    int i,j,k;
    int start,end;
    graph *edge2;
    char ch;
    edge2=(graph *)malloc(sizeof(graph)*e);//创建一个地图数组的副本
    for (i=1;i<=e;i++)
        edge2[i]=edge[i];
    int v1,v2;
    printf("                      请输入要删除的边：");
    scanf("%d,%d",&v1,&v2);
    for (i=1;i<=e;i++)
    {
        if (edge2[i].v1==v1&&edge2[i].v2==v2||edge2[i].v1==v2&&edge2[i].v2==v1)
        {
            if (edge2[i].weight==0)
            {
                printf("                      该边不在最小生成树中，按任意键继续......");
                getchar();
                return ;
            }
            edge2[i].flag=2;
            MFSet_initial();//重新初始化root数组
            for (j=1;j<=e;j++)//重新构造root数组
            {
                if(edge2[j].flag==1)
                {
                    start=MFSet_find(root,edge[j].v1);
                    end=MFSet_find(root,edge[j].v2);
                    MFSet_merge(root,start,end);
                }
            }
            for (k=1;k<=e;k++)
            {
                if(edge2[k].flag==0)
                {
                    start=MFSet_find(root,edge2[k].v1);
                    end=MFSet_find(root,edge2[k].v2);
                    if(start!=end)
                    {
                        MFSet_merge(root,start,end);
                        printf("                      在%d和%d之间铺设线路，权值为%d\n",edge2[i].v1,edge2[i].v2,edge2[i].weight);
                        edge2[k].flag=1;
                        printf("                      需要打印修改后的最小生成树吗(y/n)：");
                        fflush(stdin);
                        ch=getch();
                        if (ch=='y'||ch=='Y')
                        print(edge2,e);
                        free(edge2);
                        return ;
                    }
                    
                }
            }

        }
    }
    printf("                      未找到该条线路,按任意键继续......");
    free(edge2);
    fflush(stdin);
    getch();
}

注释写少了，大家就看看free（）有什么错吧

free（）中的参数必须是个指针，edge[i]是结构体变量，编译通过不了

哎呀，实在不好意思，犯了低级错误！！！
我第一个数组空间没用，应该是edge2=(graph *)malloc(sizeof(graph)*（e+1）)；
溢出咯，呵呵

我改过来以后可以了，谢谢帮助