BFS

#include <stdio.h>
#include <conio.h>
#define size 50

char visited_array[size];
int visited_seq = -1, f = 0, r = 0, graph[50][50], n;
char q[50];
char vertex[26];

void visit(char ch)
{
    visited_seq++;
    visited_array[visited_seq] = ch;
}

int is_visit(char ch)
{
    int i;
    for(i = 0 ; i <= visited_seq ; i++)
    {
        if(ch == visited_array[i])
            return 1; //Already visited
    }
    return 0; //Not visited before
}

void enqueue(char ch)
{
    int s;
    s = (r+1) % (size+1);
    if(s == f)
        return;
    else{
        q[s] = ch;
        r = s;
    }
}

char dequeue()
{
    if(f == r)
        return '\0';
    else
    {
        char ch;
        f = (f+1) % (size+1);
        ch = q[f];
        q[f] = '\0';
        return ch;
    }
}

void find_adjecency(char ch)
{
    int i, j;
    for(i = 0 ; i < n ; i++)
    {
        if(ch == vertex[i])
        {
            for(j = 0 ; j < n ; j++)
            {
                if(graph[i][j] == 1)
                {
                    printf("%c ", vertex[j]);
                    if(is_visit(vertex[j]) == false)
                        enqueue(vertex[j]);
                }
            }
        }
    }

}

void bfs()
{
    char ch;
    int x;
    printf("\nFrom which vertex you want to start?(1-50): ");
    scanf("%d",&x);
    enqueue(vertex[x-1]);

    while(f!=r)
    {
        ch = dequeue();
        if(is_visit(ch) == 0)
            {
                visit(ch);
            }
        find_adjecency(ch);
    }
}

void displayVisitedArray()
{
    int i;
    printf("\nVisited Sequence is:  ");
    for(i=0; i<= visited_seq ; i++)
        printf("%c ", visited_array[i]);
}

void createGraph()
{
    int i, j;
    for(i = 0 ; i < 26 ; i++)
        vertex[i] = i+65;

    printf("How many Vertex: ");
    scanf("%d", &n);
    for(i = 0 ; i < n ; i++)
    {
        for(j = 0 ; j < n ;j++)
            graph[i][j] = 0;
    }

    for(i = 0 ; i < n ; i++)
    {
        for(j = i+1 ; j < n ;j++)
        {
            printf("%c-%c exist: ", vertex[i], vertex[j]);
            scanf("%d", &graph[i][j]);
            if(graph[i][j] == 1)
                graph[j][i] = 1;
        }
    }
}
int main()
{
    createGraph();
    bfs();
    displayVisitedArray();
    getch();
}