A reminder: Maybe scanf in the higher version of VS needs to be changed to scanf_s or an error will not be reported. Specific reason: Why use scanf_s
but it can be changed: Details
#include"stdio.h"
#include"stdlib.h"
#define MaxVertexNum 50 //定义最大顶点数
typedef struct node {
//边表结点
int adjvex; //邻接点域
struct node *next;
}EdgeNode;
typedef struct vnode {
//顶点表结点
char vertex; //顶点域
EdgeNode *firstedge; //边表头指针
}VertexNode, AdjList[MaxVertexNum];
//AdjList是邻接表类型
typedef struct {
AdjList adjlist; //邻接表
int n, e; //图中当前顶点数和边数
} ALGraph; //图类型
//建立图的邻接表
void CreatALGraph(ALGraph *G)
{
int i, j, k;
char a;
EdgeNode *s; //定义边表结点
printf("Input VertexNum(n) and EdgesNum(e): ");
scanf("%d,%d", &G->n, &G->e); //读入顶点数和边数
scanf("%c", &a);
printf("Input Vertex string:");
for (i = 0; i < G->n; i++) //建立边表
{
scanf("%c", &a);
G->adjlist[i].vertex = a; //读入顶点信息
G->adjlist[i].firstedge = NULL; //边表置为空表
}
printf("Input edges,Creat Adjacency List\n");
for (k = 0; k < G->e; k++) {
//建立边表
scanf("%d%d", &i, &j); //读入边（Vi，Vj）的顶点对序号
s = (EdgeNode *)malloc(sizeof(EdgeNode)); //生成边表结点
s->adjvex = j; //邻接点序号为j
s->next = G->adjlist[i].firstedge;
G->adjlist[i].firstedge = s; //将新结点*S插入顶点Vi的边表头部
s = (EdgeNode *)malloc(sizeof(EdgeNode));
s->adjvex = i; //邻接点序号为i
s->next = G->adjlist[j].firstedge;
G->adjlist[j].firstedge = s; //将新结点*S插入顶点Vj的边表头部
}
}
//定义标志向量，为全局变量
typedef enum {
FALSE, TRUE } Boolean;
Boolean visited[MaxVertexNum];
//DFS：深度优先遍历的递归算法
void DFSM(ALGraph *G, int i)
{
//以Vi为出发点对邻接链表表示的图G进行DFS搜索
EdgeNode *p;
printf("%c", G->adjlist[i].vertex); //访问顶点Vi
visited[i] = TRUE; //标记Vi已访问
p = G->adjlist[i].firstedge; //取Vi边表的头指针
while (p) {
//依次搜索Vi的邻接点Vj，这里j=p->adjvex
if (!visited[p->adjvex]) //若Vj尚未被访问
DFSM(G, p->adjvex); //则以Vj为出发点向纵深搜索
p = p->next; //找Vi的下一个邻接点
}
}
void DFS(ALGraph *G)
{
int i;
for (i = 0; i < G->n; i++)
visited[i] = FALSE; //标志向量初始化
for (i = 0; i < G->n; i++)
if (!visited[i]) //Vi未访问过
DFSM(G, i); //以Vi为源点开始DFS搜索
}
//BFS：广度优先遍历
void BFS(ALGraph *G, int k) {
//以Vk为源点对用邻接链表表示的图G进行广度优先搜索
int i, f = 0, r = 0;
EdgeNode *p;
int cq[MaxVertexNum]; //定义FIFO队列
for (i = 0; i < G->n; i++)
visited[i] = FALSE; //标志向量初始化
for (i = 0; i <= G->n; i++)
cq[i] = -1; //初始化标志向量
printf("%c", G->adjlist[k].vertex);//访问源点Vk
visited[k] = TRUE;
cq[r] = k; //Vk已访问，将其入队。注意，实际上是将其序号入队
while (cq[f] != -1) {
//队列非空则执行
i = cq[f]; f = f + 1; //Vi出队
p = G->adjlist[i].firstedge; //取Vi的边表头指针
while (p) {
//依次搜索Vi的邻接点Vj（令p->adjvex=j）
if (!visited[p->adjvex]) {
//若Vj未访问过
printf("%c", G->adjlist[p->adjvex].vertex); //访问Vj
visited[p->adjvex] = TRUE;
r = r + 1; cq[r] = p->adjvex; //访问过的Vj入队
}
p = p->next; //找Vi的下一个邻接点
}
}//endwhile
}
//主函数
void main()
{
int i;
ALGraph *G;
G = (ALGraph *)malloc(sizeof(ALGraph));
CreatALGraph(G);
printf("Print Graph DFS: ");
DFS(G);
printf("\n");
printf("Print Graph BFS: ");
BFS(G, 3);
printf("\n");
getchar();
}
If you don’t understand the code: here is a video explaining it in detail.
In addition, another blog of mine has the code for the adjacency matrix method. If you are interested, you can go to my homepage to have a look.