DVR.c

#include <stdio.h>

struct node {
    unsigned dist[20];
    unsigned from[20];
} rt[10];

int main() {
    int costmat[20][20];
    int nodes, i, j, k, count = 0;

    printf("\nEnter the number of nodes : ");
    scanf("%d", &nodes);

    printf("\nEnter the cost matrix :\n");
    for (i = 0; i < nodes; i++) {
        for (j = 0; j < nodes; j++) {
            scanf("%d", &costmat[i][j]);

            costmat[i][i] = 0;
            rt[i].dist[j] = costmat[i][j];   // Initialize distance equal to cost matrix
            rt[i].from[j] = j;               // Initialize source node
        }
    }

    do {
        count = 0;

        for (i = 0; i < nodes; i++) {
            // Choose arbitrary vertex k
            for (j = 0; j < nodes; j++) {
                for (k = 0; k < nodes; k++) {
                    // Calculate minimum distance
                    if (rt[i].dist[j] > costmat[i][k] + rt[k].dist[j]) {
                        rt[i].dist[j] = rt[i].dist[k] + rt[k].dist[j];
                        rt[i].from[j] = k;
                        count++;
                    }

                }
            }
        }

    } while (count != 0);

    for (i = 0; i < nodes; i++){
        printf("\nFor Router %d\n", i + 1);
        for (j = 0; j < nodes; j++){
            printf("\tNode %d via %d Distance %d \n", j + 1, rt[i].from[j] + 1, rt[i].dist[j]);
        }
    }
    printf("\n");
}