图的创建遍历

采用邻接表存储结构表示图，由顶点集合和边集合构成。

typedef struct EdgeNode   //弧节点结构{     int indx; //点节点集合下标     int weight;  //权值 struct EdgeNode *next;};typedef struct VertexNode   //顶点结构{     char data; struct EdgeNode *link;};typedef struct Graphics    //图结构{int Vcount; //顶点数量int Ecount; //边数量struct VertexNode *graph[Maxsize];struct Edges *_edges[Maxsize];};

Graphics *CreateGraphics(){int vcount=0;int ecount=0;char str[Maxsize];int weight=0;int i,j=-1;Graphics *gh=(Graphics*)malloc(sizeof(Graphics));if(NULL==gh) {printf("Init Failed.\n");exit(1);}gh->Vcount=0;gh->Ecount=0;printf("input datas in order:\n");scanf("%s",str);i=0;while(str[i]!='\0'){        VertexNode *vnode=(VertexNode*)malloc(sizeof(VertexNode));if(NULL==vnode){printf("Init Failed.\n");    exit(1);}vnode->data=str[i];vnode->link=NULL;gh->graph[vcount]=vnode;vcount++;i++;}gh->Vcount=vcount;i=j=-1;printf("input edges and weight:\n");scanf("%d,%d,%d",&i,&j,&weight);    while(i!=-1&&j!=-1){        EdgeNode *enode=(EdgeNode*)malloc(sizeof(EdgeNode));if(NULL==enode){printf("Init Failed.\n");    exit(1);}//从i到jenode->indx=j;enode->next=NULL;enode->weight=weight;enode->next=gh->graph[i]->link;gh->graph[i]->link=enode;//从j到i        enode=(EdgeNode*)malloc(sizeof(EdgeNode));if(NULL==enode){printf("Init Failed.\n");    exit(1);}enode->indx=i;enode->next=NULL;enode->weight=weight;enode->next=gh->graph[j]->link;gh->graph[j]->link=enode;Edges *edge=(Edges*)malloc(sizeof(Edges));gh->_edges[gh->Ecount]=edge;gh->_edges[gh->Ecount]->from=i;gh->_edges[gh->Ecount]->to=j;gh->_edges[gh->Ecount]->weight=weight;gh->Ecount++;scanf("%d,%d,%d",&i,&j,&weight);}return gh;}

深度优先遍历：访问图的某一起始顶点p，然后由该顶点出发，访问其邻接点p1,再从p1出发，访问与p1邻接的点p2,若p2已经被访问，则舍弃继续找下一个与p1相邻接尚未被访问的点；否则由p2出发，进行类似的访问，如此进行下去，直到顶点pn（此时pn的邻接点都已被访问）为止，接着回溯到pn的前一个邻接点，查看是否有其他尚未被访问的顶点，有则访问该点，之后从该点出发，进行上述访问；若无，则继续回溯搜索。重复上述过程，直至图中所有与p连通的点都已被访问到。当然还要考虑，若该图不是连通图，则从图的顶点集合查找第一个未被访问的顶点，此时若存在这样的点，其一定是某一个非连通分量的起始顶点，重复上述过程，直至图中所有顶点都被访问过为止。

采用非递归的方式实现：

void DFS(Graphics *gh){int i=0;char joined[Maxsize]; //已遍历顶点集合if(NULL==gh||gh->Vcount==0) return;    TempStack *stack=CreateStack();for(;i<gh->Vcount||stack->top>=0;){if(stack->top<0){//空栈bool flag=false;for(int j=0;j<gh->Vcount&&(!flag);j++){  if(i>0)  {for(int k=0;k<i;k++){if(gh->graph[j]->data!=joined[k])                        flag=true;else{    flag=false;break;}}if(flag){                    joined[i++]=gh->graph[j]->data;stack->top++;stack->data[stack->top]=gh->graph[j]->link;printf("%c\n",joined[i-1]);break;}  }  else  {                 flag=true; joined[i++]=gh->graph[0]->data; stack->data[++stack->top]=gh->graph[0]->link;                 printf("%c\n",joined[i-1]);  }}}else{//栈不为空if(stack->data[stack->top]!=NULL){int j=0;for(;j<i;j++){if(joined[j]==gh->graph[stack->data[stack->top]->indx]->data){EdgeNode *ednode=stack->data[stack->top]->next;stack->data[++stack->top]=ednode;break;}}if(j>=i){//尚未加入joined[i++]=gh->graph[stack->data[stack->top]->indx]->data;                    EdgeNode *ednode=gh->graph[stack->data[stack->top]->indx]->link;stack->data[++stack->top]=ednode;printf("%c\n",joined[i-1]);}}else{//出栈while(stack->top>0&&stack->data[stack->top-1]->next==stack->data[stack->top]){stack->top--;}stack->top--;}}}}

广度优先遍历：从起始点p出发，依次访问p所有未曾访问的邻接点p1,p2,p3...pn，然后顺序的访问p1,p2,p3...pn所有未被访问过的邻接点，再从这些顶点出发，访问他们还未访问过的邻接点，重复上述过程，直至所有顶点都已被访问。有点像二叉树的层序遍历，一层一层的来。

void BFS(Graphics *gh){int i=0;int j=0;char joined[Maxsize];if(gh==NULL||gh->Vcount<=0) return;for(;i<gh->Vcount;){EdgeNode *ednode=gh->graph[i]->link;j=0;for(;j<i;j++){if(joined[j]==gh->graph[i]->data)    break;}if(j==i){            printf("%c\n",gh->graph[i]->data);    joined[i]=gh->graph[i]->data;    i++;}while(NULL!=ednode){j=0;for(;j<i;j++){if(joined[j]==gh->graph[ednode->indx]->data)   break;}if(j==i){printf("%c\n",gh->graph[ednode->indx]->data);joined[i]=gh->graph[ednode->indx]->data;i++;}ednode=ednode->next;}}}