设计一个基于DOS菜单的应用程序。要利用多级菜单实现各种功能。内容如下：
1．    无向图的基本操作及应用
①    创建无向图的邻接矩阵
②    创建无向图的邻接表
③    无向图的深度优先遍历
④    无向图的广度优先遍历
2．    无向网的基本操作及应用
①    创建无向网的邻接矩阵
②    创建无向网的邻接表
③    求最小生成树
3．    有向图的基本操作及应用
①    创建有向图的邻接矩阵
②    创建有向图的邻接表
③    拓扑排序
4．    有向网的基本操作及应用
①    创建有向网的邻接矩阵
②    创建有向网的邻接表
③    关键路径
④    单源最短路径
⑤    每对顶点之间的最短路径

这么复杂的题目，还是自己解决吧！！！

void ShowMainMenu()
{
    cout<<"\n";
    cout<<"  ***************图的基本操作及应用******************\n";
    cout<<"  *  1 无向图的基本操作及应用                      *\n";
    cout<<"  *  2 无向网的基本操作及应用                      *\n";
     cout<<"  *  3 有向图的基本操作及应用                      *\n";
    cout<<"  *  4 有向网的基本操作及应用                      *\n";
    cout<<"  *  5 退出                                        *\n";
    cout<<"  ***************************************************\n";
}

void UDG()
{
    MGraph MG;
    ALGraph ALG;
    int n;
    do
    {
        cout<<"\n";
        cout<<"  ***************无向图的基本操作及应用***************\n";
         cout<<"  *  1 创建无向图的邻接矩阵                         *\n";
        cout<<"  *  2 创建无向图的邻接表                           *\n";
         cout<<"  *  3 无向图的深度优先遍历                         *\n";
         cout<<"  *  4 无向图的广度优先遍历                         *\n";
        cout<<"  *  5 退出                                         *\n";
         cout<<"  ****************************************************\n";
        cin>>n;
        switch(n){
            case 1:
                CreatUDG_M(MG);
                break;
            case 2:
                CreatUDG_ALG(ALG);
                dispgraph(ALG);
                break;
            case 3:
                break;
            case 4:
                break;
            default:
                if (n!=5)
                    cout<<"错误，重新输入\n";
        }
    }while(n!=5);
}

void UDN()
{
    MGraph MN;
    ALGraph ALN;
    int n;
    do{
        cout<<"\n";
        cout<<"  ***************无向网的基本操作及应用***************\n";
         cout<<"  *  1 创建无向网的邻接矩阵                         *\n";
        cout<<"  *  2 创建无向网的邻接表                           *\n";
         cout<<"  *  3 prim算法求最小生成树                         *\n";
        cout<<"  *  4 kraskal算法求最小生成树                      *\n";
        cout<<"  *  5 退出                                         *\n";
         cout<<"  ****************************************************\n";
        cin>>n;
        switch(n){
            case 1:
                CreatUDN_M(MN);
                break;
            case 2:
                CreatUDN_ALG(ALN);
                dispgraph_N(ALN);
                break;
            case 3:
                break;
            case 4:
                break;
            default:
                if (n!=5)
                    cout<<"错误，重新输入\n";
        }
    }while(n!=5);
   
}

void DG()
{

    int n;
    do
    {
        cout<<"\n";
        cout<<"  ***************有向图的基本操作及应用***************\n";
         cout<<"  *  1 创建有向图的邻接矩阵                         *\n";
        cout<<"  *  2 创建有向图的邻接表                           *\n";
         cout<<"  *  3 拓扑排序                                     *\n";
        cout<<"  *  4 退出                                         *\n";
         cout<<"  ****************************************************\n";
        cin>>n;
        switch(n){
            case 1:
               
                break;
            case 2:

                break;
            case 3:
                break;
            default:
                if (n!=4)
                    cout<<"错误，重新输入\n";
        }
    }while(n!=4);
}

void DN()
{

    int n;
    do{
        cout<<"\n";
        cout<<"  ***************有向网的基本操作及应用***************\n";
         cout<<"  *  1 创建有向网的邻接矩阵                         *\n";
        cout<<"  *  2 创建有向网的邻接表                           *\n";
         cout<<"  *  3 关键路径                                     *\n";
        cout<<"  *  4 单源顶点最短路径问题                         *\n";
        cout<<"  *  5 每对顶点间最短路径问题                       *\n";
        cout<<"  *  6 退出                                         *\n";
         cout<<"  ****************************************************\n";
        cin>>n;
        switch(n){
            case 1:
                break;
            case 2:
                break;
            case 3:
                break;
            case 4:
                break;
            case 5:
                break;
            default:
                if (n!=6)
                    cout<<"错误，重新输入\n";
        }
    }while(n!=6);
   
}

void main()
{
    int n;
    do{
        ShowMainMenu();
        cin>>n;
        switch(n){
            case 1:
                UDG();
                break;
            case 2:
                UDN();
                break;
            case 3:
                DG();
                break;
            case 4:
                DN();
                break;
            default:
                if (n!=5)
                    cout<<"错误，重新输入\n";
        }
    }while(n!=5);
}