DIJKSRTRA'S ALGORITHM

/*Implementation of Shortest Path Algorithm(DIJKSRTRA's ALGORITHM) in C*/

#include< stdio.h>
#include< conio.h>
#include< process.h>
#include< string.h>
#include< math.h>
#define IN 99
#define N 6

int dijkstra(int cost[][N], int source, int target);

void main()
{
int cost[N][N],i,j,w,ch,co;
int source, target,x,y;
clrscr();
printf("\tShortest Path Algorithm(DIJKSRTRA's ALGORITHM\n\n");
for(i=1;i< N;i++)
for(j=1;j< N;j++)
cost[i][j] = IN;
for(x=1;x< N;x++)
{
for(y=x+1;y< N;y++)
{
printf("Enter the weight of the path between node %d and %d: ",x,y);
scanf("%d",&w);
cost [x][y] = cost[y][x] = w;
}
printf("\n");
}
printf("\nEnter The Source:");
scanf("%d", &source);
printf("\nEnter The target");
scanf("%d", &target);
co = dijsktra(cost,source,target);
printf("\nShortest Path: %d",co);
getch();
}

int dijsktra(int cost[][N],int source,int target)
{
int dist[N],prev[N],selected[N]={0},i,m,min,start,d,j;
char path[N];
for(i=1;i< N;i++)
{
dist[i] = IN;
prev[i] = -1;
}
start = source;
selected[start]=1;
dist[start] = 0;
while(selected[target] ==0)
{
min = IN;
m = 0;
for(i=1;i< N;i++)
{
d = dist[start] +cost[start][i];
if(d< dist[i]&&selected[i]==0)
{
dist[i] = d;
prev[i] = start;
}
if(min>dist[i] && selected[i]==0)
{
min = dist[i];
m = i;
}
}
start = m;
selected[start] = 1;
}
start = target;
j = 0;
while(start != -1)
{
path[j++] = start+65;
start = prev[start];
}
path[j]='\0';
strrev(path);
printf("%s", path);
return dist[target];
}
/***** Output *********

Shortest Path Algorithm(DIJKSRTRA's ALGORITHM

Enter the weight of the path between node 1 and 2: 2
Enter the weight of the path between node 1 and 3: 3
Enter the weight of the path between node 1 and 4: 4
Enter the weight of the path between node 1 and 5: 5

Enter the weight of the path between node 2 and 3: 5
Enter the weight of the path between node 2 and 4: 2
Enter the weight of the path between node 2 and 5: 3

Enter the weight of the path between node 3 and 4: 1
Enter the weight of the path between node 3 and 5: 4

Enter the weight of the path between node 4 and 5: 5



Enter The Source:2

Enter The target4
CE
Shortest Path: 2
*/