用prim算法求给定无向连通网的最小生成树，输入无向连通网的顶点数，起始顶点及无向连通网各边的权值，输出边和权值，C语言

以下是用Prim算法求给定无向连通网的最小生成树的C语言代码：

#include <stdio.h>
#include <limits.h>

#define MAX_VERTICES 100

int graph[MAX_VERTICES][MAX_VERTICES];
int parent[MAX_VERTICES];
int key[MAX_VERTICES];
int visited[MAX_VERTICES];

int minKey(int n) {
    int min = INT_MAX, min_index;
    for (int v = 0; v < n; v++) {
        if (visited[v] == 0 && key[v] < min) {
            min = key[v];
            min_index = v;
        }
    }
    return min_index;
}

void primMST(int n, int start) {
    for (int i = 0; i < n; i++) {
        key[i] = INT_MAX;
        visited[i] = 0;
    }

    key[start] = 0;
    parent[start] = -1;

    for (int count = 0; count < n - 1; count++) {
        int u = minKey(n);
        visited[u] = 1;

        for (int v = 0; v < n; v++) {
            if (graph[u][v] && visited[v] == 0 && graph[u][v] < key[v]) {
                parent[v] = u;
                key[v] = graph[u][v];
            }
        }
    }

    printf("Edges \tWeight\n");
    for (int i = 1; i < n; i++) {
        printf("%d - %d \t%d\n", parent[i], i, graph[i][parent[i]]);
    }
}

int main() {
    int n, start;
    printf("Enter the number of vertices: ");
    scanf("%d", &n);
    printf("Enter the start vertex: ");
    scanf("%d", &start);

    printf("Enter the adjacency matrix:\n");
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            scanf("%d", &graph[i][j]);
        }
    }

    primMST(n, start);

    return 0;
}

其中，`graph` 为邻接矩阵，`parent` 为每个顶点在最小生成树中的父节点，`key` 为每个顶点到最小生成树的距离，`visited` 用于标记顶点是否已经被访问。`minKey` 函数用于寻找未访问顶点中 key 值最小的顶点，`primMST` 函数用于实现 Prim 算法求解最小生成树，最后输出每条边和权值。