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Breadth First Search(BFS) Program in C.
#include<stdio.h>
int a[20][20], q[20], visited[20], n, i, j, f = 0, r = -1;
void bfs(int v) {
for(i = 1; i <= n; i++)
if(a[v][i] && !visited[i])
q[++r] = i;
if(f <= r) {
visited[q[f]] = 1;
bfs(q[f++]);
}
}
void main() {
int v;
printf("\n Enter the number of vertices:");
scanf("%d", &n);
for(i=1; i <= n; i++) {
q[i] = 0;
visited[i] = 0;
}
printf("\n Enter graph data in matrix form:\n");
for(i=1; i<=n; i++) {
for(j=1;j<=n;j++) {
scanf("%d", &a[i][j]);
}
}
printf("\n Enter the starting vertex:");
scanf("%d", &v);
bfs(v);
printf("\n The node which are reachable are:\n");
for(i=1; i <= n; i++) {
if(visited[i])
printf("%d\t", i);
else {
printf("\n Bfs is not possible. Not all nodes are reachable");
break;
}
}
}
@kausar28
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kausar28 commented Oct 14, 2018

what is the input

@mvrozanti
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mvrozanti commented Mar 19, 2019

@kausar28 the starting vertex

@utkzas
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utkzas commented Nov 12, 2020

is it for a graph also?

@Alishaaliee
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Alishaaliee commented Nov 17, 2020

this code is taking input in loop.

@bhavesh0908
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bhavesh0908 commented Sep 16, 2022

can we give the starting vertex as default

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