# BFS – C code

```#include
#include

/*
Funtion Name: bfs
Input Params: Graph input as matrix, number of vertices and source vertex
Return Type:  void
Description:  performs bfs traversal on the given graph
*/
void bfs(int m, int v, int source)
{
/// A queue will be used during the traversal
int queue;
int front = 0;
int rear = 0;

/// Temporary variables
int u;
int i;

/// Array to maintain the visited vertices
int visited;

/// Set all the vertices to not visited
for (i= 0; i < v; i ++)
visited[i] = 0;

/// Initilaize the queue with source and mark it visited
queue[rear] = source;
visited = 1;

printf("The BFS Traversal is... \n");

/// Until the queue is empty
while (front <= rear)
{
/// Pick the vertex from queue front
/// This is also when we mark the traversal and print it
u = queue[front];
printf("%d\t", u);
front = front + 1;

/// All the vertices that are reachable from considered vertex
/// and not yet visited,
/// Mark them as visited and Add them to queue
for(i=0;i<<v;i++)
{
if(m[u][i] == 1 && visited[i] == 0)
{
visited[i] = 1;
rear = rear + 1;
queue[rear] = i;
}
}
}
}

int main()
{
/// Variable to hold the number of vertices
int v = 5;

/// Variable to hold the graph as matrix
int m =
{
{0, 1, 1, 0, 0},
{1, 0, 0, 1, 1},
{1, 0, 0, 0, 1},
{0, 1, 0, 0, 0},
{0, 1, 1, 0, 0}
};

/// Variable to hold source vertex
int source = 4;

/// Call the bfs traversal
bfs(m, v, source);

return 0;
}
```