1.递归

void DFS(Graph G, int v)
{
    visited[v] = 1;
    printf("%c ", G.vexs[v]);
    for (int i = 0; i < G.vexnum; i++) 
    {
        if (!visited[i] && G.arcs[v][i]) 
            DFS(G, i);
    }
}

2.非递归

#include <stack>
#include <iostream>
using namespace std;
void DFS(Graph G, int v) 
{
    stack<int> st;
    st.push(v);
    visited[v] = 1;
    cout << G.vexs[v] << " ";

    while (!st.empty()) 
    {
        int index = 0;
        bool found = false;

        //它可能和多个点有边 按照下标递增找到第一个
        int top = st.top();
        for (index = 0; index < G.vexnum; index++) 
        {
            if (!visited[index] && G.arcs[top][index])
            {
                found = true;
                break;
            }
        }

        //但凡找到
        if (found)
        {
            st.push(index);
            visited[index] = 1;
            cout << G.vexs[index] << " ";
        }
        else
            st.pop();
    }
}