Desigine a NFA but not working - c

Question

I designed this NFA - where I input a string, and the output is Accepted if this NFA accept it else Not accepted.
My code is here -
#include <stdio.h>
#include <stdlib.h>
int accepted = 1;
struct node
{
char first, second;
struct node *left, *right;
};
int main()
{
struct node *stage, *start, *temp;
char A[50000], data;
printf("String: ");
gets(A);
int i;
for(i=0; i<strlen(A); i++)
{
if(i==0)
{
stage=(struct node*)malloc(sizeof(struct node));
if(A[i] == '0')
{
stage->first = 'B';
stage->second = 'A';
}
else if(A[i] == '1')
{
stage->first = 'A';
stage->second = '\0';
}
stage->left = '\0';
start = stage;
temp = stage;
stage->right = '\0';
}
else
{
stage=(struct node*)malloc(sizeof(struct node));
temp->right = stage;
stage->left = temp;
if(A[i] == '0')
{
if(temp->first = 'A')
{
stage->first = 'B';
stage->second = 'A';
}
else if(temp->first = 'B')
{
stage->first = '\0';
stage->second = '\0';
}
else if(temp->first = 'C')
{
stage->first = '\0';
stage->second = '\0';
}
else if(temp->first = '\0')
{
while(1)
{
stage = stage->left;
temp = stage->left;
stage->right = '\0';
i--;
if(i == 0)
{
accepted = 0;
break;
}
if(stage->second != '\0')
{
stage->first = stage->second;
stage->second = '\0';
break;
}
}
}
}
else if(A[i] == '1')
{
if(temp->first = 'A')
{
stage->first = 'A';
stage->second = '\0';
}
else if(temp->first = 'B')
{
stage->first = 'C';
stage->second = '\0';
}
else if(temp->first = 'C')
{
stage->first = 'C';
stage->second = '\0';
}
else if(temp->first = '\0')
{
while(1)
{
stage = stage->left;
temp = stage->left;
stage->right = '\0';
i--;
if(i == 0)
{
accepted = 0;
break;
}
if(stage->second != '\0')
{
stage->first = stage->second;
stage->second = '\0';
break;
}
}
}
}
temp = stage;
stage->right = '\0';
}
}
temp = start;
printf("\n");
while(1)
{
printf("%c => ", temp->first);
temp = temp->right;
if(temp->right == '\0')
{
data = temp->first;
break;
}
}
if(accepted && data == 'C') printf("\n\nAccepted.\n");
else printf("\n\nNot accepted.\n");
return 0;
}
Please help me to find, what's wrong there.