//shortest_path.c
#include<stdio.h>
#include<stdlib.h>//With the file
#include<string.h>//Available gets (), puts ()
#include"shortest_path.h"
#define MAX 32767
#define MENU " Welcome to the navigation system! n========== The menu ===========n0 , load the north field map n1 Create a map n2 , query the shortest path n3 , exit n========== The menu ===========n"
struct stmap map;//Undirected network
const char *filepath1="D:\spots.dat";
const char *filepath2="D:\paths.dat";
int load1()
{
FILE *fp;
int i;
fp=fopen(filepath1,"r");
if(fp==NULL){printf("spots File open exception, read failed ");return -1;}
fread(&map.spotnum,sizeof(int),1,fp);
for(i=0;i<map.spotnum;i++)
{
fread(map.spot[i].name,sizeof(char),10,fp);
fread(map.spot[i].intro,sizeof(char),20,fp);
}
fclose(fp);
return 0;
}
int load2()
{
FILE *fp;
int i,j;
fp=fopen(filepath2,"r");
if(fp==NULL){printf("paths File open exception, read failed ");return -1;}
fread(&map.pathmatrix,sizeof(int),1,fp);
for(i=0;i<map.spotnum;i++)
for(j=0;j<map.spotnum;j++)
fread(&map.pathmatrix[i][j],sizeof(int),1,fp);
fclose(fp);
return 0;
}
void loadmap()
{
if(load1()==0)
printf("spot Read the success n");
else
printf("spot Read the failure n");
if(load2()==0)
printf("path Read the success n");
else
printf("path Read the failure n");
}
void drawmap()//Direct input
{
int i;
int a,b;
char s1[10],s2[10];
printf(" How many spots are there? (<=20)");//map.spotmun
fflush(stdin);
scanf("%d",&map.spotnum);
printf(" How many direct links are there between the scenic spots? ");//map.pathnum
fflush(stdin);//Clear the keyboard buffer in "stdio.h"
scanf("%d",&map.pathnum);
for(a=0;a<map.spotnum;a++)//initialize map
for(b=0;b<map.spotnum;b++)
{
if(a==b)map.pathmatrix[a][b]=0;
else map.pathmatrix[a][b]=MAX;
}
for(i=0;i<map.spotnum;i++){
printf(" Please enter the first %d The name of each attraction ( <=10letters ) ",i+1);
fflush(stdin);
gets(map.spot[i].name);
printf(" Please enter the first %d An introduction to the four attractions ( <=20letters ) ",i+1);
fflush(stdin);
gets(map.spot[i].intro);
}//Enter map.spot[].name; The map. The spot []. Intro
for(i=0;i<map.pathnum;i++){
do{
printf(" Please enter the first %d The starting point of a path ",i+1);
fflush(stdin);
gets(s1);
for(a=0;a<map.spotnum;a++)
if(!strcmp(map.spot[a].name,s1))break;//Find the spot number
if(a==map.spotnum)printf(" This scenic spot does not exist. Please enter again. n");
}while(a==map.spotnum);
do{
printf(" Please enter the first %d The end of a path ",i+1);
fflush(stdin);
gets(s2);
for(b=0;b<map.spotnum;b++)
if(!strcmp(map.spot[b].name,s2))break;
if(b==map.spotnum)printf(" This scenic spot does not exist. Please enter again. n");
}while(b==map.spotnum);
printf(" Please enter the first %d The length of the path ",i+1);
fflush(stdin);
scanf("%d",&map.pathmatrix[a][b]);
map.pathmatrix[b][a]=map.pathmatrix[a][b];//Input path length
}
}
void shortestpath()//Shortest path, input starting point, output path and distance
{
struct stspath spath[20];
int s,t,v,w,min;
char s1[10],s2[10];
int pathorder[20];
struct stspath *p;//pathorder
do{
printf(" Please enter the starting point ");//Find the starting spot number
fflush(stdin);
gets(s1);
for(s=0;s<map.spotnum;s++)
if(!strcmp(map.spot[s].name,s1))break;
if(s==map.spotnum)printf(" This scenic spot does not exist. Please enter again. n");
}while(s==map.spotnum);
do{
printf(" Please enter endpoint ");//Find the destination's spot number
fflush(stdin);
gets(s2);
for(t=0;t<map.spotnum;t++)
if(!strcmp(map.spot[t].name,s2))break;
if(t==map.spotnum)printf(" This scenic spot does not exist. Please enter again. n");
}while(t==map.spotnum);
for(v=0;v<map.spotnum;v++)//initialize spath
{
spath[v].length=MAX;
spath[v].in=0;
}
spath[s].in=1;
spath[s].length=0;
spath[s].pior=NULL;
v=s;
while(v!=t){
for(w=0;w<map.spotnum;w++)
if((!spath[w].in)&&(spath[w].length>spath[v].length+map.pathmatrix[v][w])){
spath[w].length=spath[v].length+map.pathmatrix[v][w];
spath[w].pior=&spath[v];
}
min=MAX;
for(w=0;w<map.spotnum;w++)
if((!spath[w].in)&&(spath[w].length<min)){
min=spath[w].length;
v=w;
}
spath[v].in=1;
}
printf(" The shortest path length is zero %d, The shortest path is: n",spath[t].length);//print path
for(v=0,p=&spath[t];p->pior!=NULL;p=p->pior)
{
pathorder[v]=p-spath;
v++;
}
pathorder[v]=s;
for(;v>=0;v--)
printf("%10s",map.spot[pathorder[v]].name);
}
void main()
{
int menu=1;
printf(MENU);
while(menu!=3)
{
printf("n Please enter your options (Numbers) n");
fflush(stdin);
scanf("%d",&menu);
switch (menu)
{
case 0: loadmap();printf("n Map loading completed n");break;
case 1: drawmap();printf("n The new complete n");break;
case 2: shortestpath();printf("n Query completed n");break;
}
}
printf(" Thanks for using! ");
}
2. [ file ] shortest_path.h ~ 430B download (2)
#ifndef _SHORTEST_PATH_H_
#define _SHORTEST_PATH_H_
struct stspot{//The apex of the attraction
char name[11];//No more than 10
char intro[20];//No more than 20
};
struct stmap{// The whole Undirected network
stspot spot[20];//Dot, scenic spot vector
int pathmatrix[20][20];//Edge, the adjacency matrix of paths
int spotnum;
int pathnum;
};
struct stspath//Find the shortest path when the array of attractions
{
stspath * pior;
int in;// can be boolen
int length;
};
#endif
