Access violation in Breadth First Search - c

Question

I've written this code for BFS, but after showing the result it crashes. I don't find anything wrong with my code. Here's the code
I think this is pointer related problem, because I got the same problem because I did not allocate memeory. Visual studio debugger shows there's a problem in this function.
int getAdjUnvisitedVertex(int vertexIndex) {
for (int j = 0; j < vertexCount; ++j) {
if (adjMatrix[vertexIndex][j] == 1 && vertices[j]->visited == false) { //Is there anything wrong in this logic?
return j;
}
}
return 0;
}
Any help will be much appreciated. This is my full code. DFS is working, its BFS that causing problems.
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<malloc.h>
#include<stdbool.h>
#define SIZE 50
int vertexCount;
struct vertex {
char label;
bool visited;
};
struct vertex *vertices[SIZE];
int adjMatrix[SIZE][SIZE];
int stack[SIZE];
int queue[SIZE];
int top = -1;
int front = -1;
int rear = -1;
void menu();
void addVertex();
void addEdges();
void push(char);
void pop();
void enQueue(char);
int deQueue();
void displayAdjMatrix();
void displayVertex(int);
int getAdjUnvisitedVertex(int);
void DFS();
void BFS();
bool isStackEmpty();
bool isQueueEmpty();
int main() {
menu();
addVertex();
addEdges();
puts("\nDepth first search:");
DFS();
puts("\nBreadth first search:");
BFS();
}
void menu() {
puts("How many vertices?");
scanf("%d", &vertexCount);
}
void addVertex() {
int ascii = (int)'A';
puts("Vertices are:");
for (int i = 0; i < vertexCount; ++i, ++ascii) {
vertices[i] = (struct vertex*)calloc(vertexCount, sizeof(struct vertex));
vertices[i]->label = (char)ascii;
vertices[i]->visited = false;
printf("%c ", vertices[i]->label);
}
}
void addEdges() {
puts("\nEnter edges:");
for (int i = 0; i < vertexCount; ++i) {
for (int j = i + 1; j < vertexCount; ++j) {
printf("%c->%c: ", vertices[i]->label, vertices[j]->label);
scanf("%d", &adjMatrix[i][j]);
if (adjMatrix[i][j] == 1) {
adjMatrix[j][i] = 1;
}
}
}
}
void displayAdjMatrix() {
for (int i = 0; i < vertexCount; ++i) {
for (int j = 0; j < vertexCount; ++j) {
printf("%d\t", adjMatrix[i][j]);
}
puts("");
}
}
void push(char data) {
if (top == SIZE - 1) {
puts("Overflow!");
return;
}
stack[++top] = data;
}
void pop() {
if (top == -1) {
puts("Underflow!");
return;
}
stack[top--];
}
int getAdjUnvisitedVertex(int vertexIndex) {
for (int j = 0; j < vertexCount; ++j) {
if (adjMatrix[vertexIndex][j] == 1 && vertices[j]->visited == false) {
return j;
}
}
return 0;
}
void displayVertex(int vertexIndex) {
printf("%c ", vertices[vertexIndex]->label);
}
void DFS() {
vertices[0]->visited = true;
displayVertex(0);
push(0);
while (!isStackEmpty()) {
int unvisitedVertex = getAdjUnvisitedVertex(stack[top]);
if (!unvisitedVertex) {
pop();
}
else {
vertices[unvisitedVertex]->visited = true;
displayVertex(unvisitedVertex);
push(unvisitedVertex);
}
}
for (int i = 0; i < vertexCount; ++i) {
vertices[i]->visited = false;
}
}
bool isStackEmpty() {
if (top == -1) {
return true;
}
return false;
}
bool isQueueEmpty() {
if (front == -1) {
return true;
}
return false;
}
void enQueue(char data) {
if (rear == SIZE - 1) {
puts("Queue is full!");
return;
}
if (front == -1) {
++front;
}
queue[++rear] = data;
}
int deQueue() {
if (front == - 1) {
puts("Queue is empty!");
return 0;
}
int deleted;
deleted = queue[front];
queue[front++] = 0;
return deleted;
}
void BFS() {
vertices[0]->visited = true;
displayVertex(0);
enQueue(0);
while (!isQueueEmpty()) {
int temp = deQueue();
int unvisitedVertex;
while(unvisitedVertex = getAdjUnvisitedVertex(temp)) {
vertices[unvisitedVertex]->visited = true;
displayVertex(unvisitedVertex);
enQueue(unvisitedVertex);
}
}
for (int i = 0; i < vertexCount; ++i) {
vertices[i]->visited = false;
}
}