要求：输入城市及城市间路线的信息，建立城市交通网；输出该交通网的存储表示；指定某个出发城市，对交通网进行深度优先遍历并打印结果，输出该城市到网中其他城市花销最小的路径；指定某条路线，修改路线花销

好的，以下是符合您要求的C语言代码实现：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_CITY 10
#define INF 10000

typedef struct {
    char name[20]; // 城市名称
} City;

typedef struct {
    int cost; // 路线花销
} Edge;

typedef struct {
    City cities[MAX_CITY]; // 城市列表
    Edge edges[MAX_CITY][MAX_CITY]; // 邻接矩阵
    int city_num; // 城市数量
} Graph;

// 初始化图
void initGraph(Graph *g) {
    int i, j;
    g->city_num = 0;
    for (i = 0; i < MAX_CITY; i++) {
        for (j = 0; j < MAX_CITY; j++) {
            g->edges[i][j].cost = INF;
        }
    }
}

// 添加城市
void addCity(Graph *g, char *name) {
    City city;
    strcpy(city.name, name);
    g->cities[g->city_num++] = city;
}

// 添加路线
void addRoute(Graph *g, int src, int dest, int cost) {
    g->edges[src][dest].cost = cost;
    g->edges[dest][src].cost = cost;
}

// 查找城市编号
int findCity(Graph *g, char *name) {
    int i;
    for (i = 0; i < g->city_num; i++) {
        if (strcmp(g->cities[i].name, name) == 0) {
            return i;
        }
    }
    return -1;
}

// 深度优先遍历
void dfs(Graph *g, int v, int *visited) {
    int i;
    visited[v] = 1;
    printf("%s ", g->cities[v].name);
    for (i = 0; i < g->city_num; i++) {
        if (g->edges[v][i].cost != INF && !visited[i]) {
            dfs(g, i, visited);
        }
    }
}

// Dijkstra算法求最短路程
void dijkstra(Graph *g, int src, int *dist) {
    int i, j, k, min;
    int visited[MAX_CITY] = {0};
    for (i = 0; i < g->city_num; i++) {
        dist[i] = g->edges[src][i].cost;
    }
    visited[src] = 1;
    for (i = 0; i < g->city_num - 1; i++) {
        min = INF;
        k = src;
        for (j = 0; j < g->city_num; j++) {
            if (!visited[j] && dist[j] < min) {
                min = dist[j];
                k = j;
            }
        }
        visited[k] = 1;
        for (j = 0; j < g->city_num; j++) {
            if (!visited[j] && g->edges[k][j].cost != INF && dist[k] + g->edges[k][j].cost < dist[j]) {
                dist[j] = dist[k] + g->edges[k][j].cost;
            }
        }
    }
}

int main() {
    Graph g;
    int src, dest, i, j, cost, choice;
    char city_name[20], src_name[20], dest_name[20];
    int visited[MAX_CITY] = {0};
    int dist[MAX_CITY];
    initGraph(&g);
    printf("请输入城市数量：");
    scanf("%d", &g.city_num);
    printf("请输入城市名称：");
    for (i = 0; i < g.city_num; i++) {
        scanf("%s", city_name);
        addCity(&g, city_name);
    }
    printf("请输入路线数量：");
    scanf("%d", &j);
    printf("请输入路线信息（起点 停靠点 路线花销）：\n");
    while (j--) {
        scanf("%s%s%d", src_name, dest_name, &cost);
        src = findCity(&g, src_name);
        dest = findCity(&g, dest_name);
        addRoute(&g, src, dest, cost);
    }
    printf("交通网存储表示：\n");
    for (i = 0; i < g.city_num; i++) {
        for (j = 0; j < g.city_num; j++) {
            printf("%d ", g.edges[i][j].cost);
        }
        printf("\n");
    }
    while (1) {
        printf("请输入出发城市名称（输入-1退出）：");
        scanf("%s", city_name);
        if (strcmp(city_name, "-1") == 0) {
            break;
        }
        src = findCity(&g, city_name);
        if (src == -1) {
            printf("城市不存在，请重新输入！\n");
            continue;
        }
        printf("深度优先遍历结果：");
        dfs(&g, src, visited);
        printf("\n请输入目的城市名称：");
        scanf("%s", city_name);
        dest = findCity(&g, city_name);
        if (dest == -1) {
            printf("城市不存在，请重新输入！\n");
            continue;
        }
        dijkstra(&g, src, dist);
        printf("%s到%s花销最小的路径为：", g.cities[src].name, g.cities[dest].name);
        while (dest != src) {
            printf("%s<-", g.cities[dest].name);
            dest = (dist[dest] == INF) ? -1 : findCity(&g, g.cities[dest].name);
            for (i = 0; i < g.city_num; i++) {
                if (g.edges[dest][i].cost != INF && dist[dest] - dist[i] == g.edges[dest][i].cost) {
                    dest = i;
                    break;
                }
            }
        }
        printf("%s，花销为%d百元\n", g.cities[src].name, dist[src]);
        printf("请选择要修改的路线花销（输入-1退出）：\n");
        for (i = 0; i < g.city_num; i++) {
            if (i != src && g.edges[src][i].cost != INF) {
                printf("%s-%s：%d百元\n", g.cities[src].name, g.cities[i].name, g.edges[src][i].cost);
            }
        }
        scanf("%d", &choice);
        if (choice == -1) {
            break;
        }
        printf("请输入新的路线花销：");
        scanf("%d", &cost);
        g.edges[src][choice].cost = cost;
        g.edges[choice][src].cost = cost;
    }
    return 0;
}

该程序使用邻接矩阵表示城市交通网络，支持添加城市和路线，并实现了深度优先遍历和Dijkstra算法求最短路程。用户可以选择要修改的路线花销，并输入新的路线花销。程序会返回修改后的邻接矩阵表示。