Thread: dijkstra's algorithm in c language, having problems, please help

Does this code look like a proper dijkstra's algorithm and what am I doing wrong?

Code:

/* dijkstra's algorithm in in c language */


#include <stdio.h>
#include <cstdlib.h>
#include <graph.h>
#include <math.h>
#define IN=1000000
#define N 6
int main() {
int i, j, w;
cost[i][j];
cost[u][j]-cost[i][j]=e;
cost[i+1][j+1]-cost[i][j]=w
cost();


/*   edge     0-1    */
cost[0].i= 0
cost[0].u=1
cost[0].w=1


/*   edge    1-2     */
cost[1[.i=1
cost[1].u=2
cost[1].w=3


/*   edge   1-3      */
cost[2].i=1
cost[2].u=3
cost[2].w=4


/*   edge   2-4      */
cost[3].i=2
cost[3].u=4
cost[3].w=1


/*   edge     3-5    */
cost[4].i=3
cost[4].u=5
cost[4].w=2


/*   edge    4-6     */
cost[5].i=4
cost[5].u=6
cost[5].w=6


/*   edge    3-4     */
cost[6].i=3
cost[6].u=4
cost[6].w=5


return cost;
}


int deletingfromqueue(){
adjacent();
if(visited>0){
u=visited[u];
visited=visited[i]-visited[u]
visited[i]=dist[i][j]
compare();
show();
if(cost[u]-cost[i]=w){
 for(i=1; i<=N-1; i++){
  for(j=1; j<=N; j++)
    cost[i][j]=cost[i+1][j+1];
     }
N--
  }
}
typedef struct{
int i, u
int w
}e;


bool compare(const void *i, const void *u){
x=i
x1=u
if(i -> w  <  u ->w)
return -1;
if(i-> w  <  u-> w)
return 1;
return (0);
}


int cost(){
dist();
int visited[N], memset(visited, 0, sizeof(visited));
cost[i][j]=cost[6][6]
int i, j;
adjacent();
printf("Enter the elements\n", i+1, j+1);
scanf("%d", &cost[i][j])
printf("Enter number of nodes\n")
scanf("%d", &N)
counter=malloc(sizeof(int*) *N);
visited=malloc(sizeof(int*) *deletingfromqueue);
 for(i=0; i<N; N++){
   for(j=0; j<N; j++){
    scanf("%d", &cost[i][j])
      if(cost[i][j]=0){
         cost[i][j]= IN
         visited[i]=0
            }
      }
}
if(N>0; N++){
counter++
}


int dist(){
dist[i]= IN
prior[i]= -1
printf("Enter starting node\n")
scanf("%d", &u);
cost();
if(cost[i][j]=cost[i+1][j]){
N= N-1
}
startnode=u;
for(i=0; i<N; i++){
  for(j=0; j<N; j++){
    dist[i]=0
 adjacent();
cost[i][j]= adjacent(u,i)
N--
prio[i]= prior[i+1];
counter++;
for (p=0; p<N; p++){
  if(cost[i][p] > cost[i][j]){
     cost[i][p]= cost[i][j] + w 
          }
      }
}


int adjacent(){
int i=0;
for(i=0; i<N; i++){
if(!visited[i]&&dist[i] > dist[u]){
  dist[i]+cost[v][i]=dist[i]
}
if(dist>dist[i]&&visited[i]){
  dist=dist[i]
  prior=1
  visited[i]=1
}
if(cost[0][i]&&!visited[i]{
  if(dist[v]+dist[i]<dist[i]+w){
    if(!dist[v]=prior++&&dist[i]+w){
      if(dist[v] < dist[w]){
         dist[w]= dist[i]+cost[w];
            dist[w]=dist[i];
           deletingfromqueue();
            qsort();
                         }
                   }
             }
}


int qsort(cost, N, sizeof(int), (*compare), (const void *i, const void *u)){
cost[u][j]>cost[i][j]
e=edge
h=0
if(e->i  <  h->i)
return -1;
else if(e->i  >  h->i)
return 1;
else if(e->u  <  h->u)
return -1;
else
return(e->u  >  h->u)
show();
}


int show(){
int i, j;
for(i=1; i<N=N; i++){
  for(j=1; j<=N; j++){
    printf("%d", cost[i][j]);
      }
   }
return dist;

No, it doesn't look like a proper Djikstra's algorithm. Where did you get it? It's full of all different kinds of errors, invalid code and undefined behavior.

Apart from that, the formatting is crappy. Next time, please make sure your code is properly indented. Also, please provide all relevant information, such as non-standard headers like cstdlib.h¹, graph.h and map.h.

¹There is stdlib.h, which is a standard C header, and cstdlib, which is a C++ header that mimics stdlib.h for C++ compatability with C.

Well I looked at Dijkstra's algorithm so I tried to put in the cost matrix and distance matrix and code to find adjacent nodes. Then I added in what was supposed to be a code to enter the weights n to compare different distances. Can you pinpoint where the errors are a d if anything is correct in the code?

You are spot on actually. I looked at others code from around the web, learned what strategies the used for certain parts and rewrote it in my own way. I did take some aspects of kruskal's algorithm. And yes I am a beginner when in comes to c, quite fresh actually. You're right I should learn the basics properly instead of rushing into the language