Question: Can someone explain this code for tower of hanoi for me . I would like to know the flow and how it works . #include
Can someone explain this code for tower of hanoi for me . I would like to know the flow and how it works .
#include
#include
#include
//stack first
struct node1
{
//keeps data record
int data1;
//keep record of next node
struct node1 *next1;
}*top1 = NULL, *p1 = NULL, *np1 = NULL;
//stack second
struct node2
{
int data2;
struct node2 *next2;
}*top2 = NULL, *p2 = NULL, *np2 = NULL;
struct node3
{
int data3;
struct node3 *next3;
}*top3 = NULL, *p3 = NULL, *np3 = NULL;
//push data to stack
void push1(int data)
{
//create new node1
np1 =(struct node1 *)malloc(sizeof(struct node1));
//store the data to data link
np1->data1 = data;
//set next to null
np1->next1 = NULL;
//if top null set it to null
if (top1 == NULL)
{
top1 = np1;
}
else
{
//else next will be new entry
np1->next1 = top1;
top1 = np1;
}
}
int pop1()
{
int b = 999;
//if top is null return 99
if (top1 == NULL)
{
return b;
}
else
{
//get top
p1 = top1;
//move top to past entry
top1 = top1->next1;
//return data
return(p1->data1);
//delete p1
delete(p1);
}
}
void push2(int data)
{
np2 =(struct node2 *)malloc(sizeof(struct node2));
np2->data2 = data;
np2->next2 = NULL;
if (top2 == NULL)
{
top2 = np2;
}
else
{
np2->next2 = top2;
top2 = np2;
}
}
int pop2()
{
int b = 999;
if (top2 == NULL)
{
return b;
}
else
{
p2 = top2;
top2 = top2->next2;
return(p2->data2);
delete(p2);
}
}
void push3(int data)
{
np3 =(struct node3 *)malloc(sizeof(struct node3));
np3->data3 = data;
np3->next3 = NULL;
if (top3 == NULL)
{
top3 = np3;
}
else
{
np3->next3 = top3;
top3 = np3;
}
}
int pop3()
{
int b = 999;
if (top3 == NULL)
{
return b;
}
else
{
p3 = top3;
top3 = top3->next3;
return(p3->data3);
delete(p3);
}
}
int top_of_stack()
{
if (top1 != NULL && top1->data1 == 1 )
{
return 1;
}
else if (top2 != NULL && top2->data2 == 1)
{
return 2;
}
else if (top3 != NULL && top3->data3 == 1)
{
return 3;
}
else
return 0;
}
void display1()
{
printf(" ");
struct node1 *p1;
p1 = top1;
printf("Tower1-> \t");
while (p1 != NULL)
{
printf("%d\t",p1->data1);
p1 = p1->next1;
}
printf(" ");
}
void display2()
{
struct node2 *p2;
p2 = top2;
printf("Tower2-> \t");
while (p2 != NULL)
{
printf("%d\t",p2->data2);
p2 = p2->next2;
}
printf(" ");
}
void display3()
{
struct node3 *p3;
p3 = top3;
printf("Tower3-> \t");
while (p3 != NULL)
{
printf("%d\t",p3->data3);
p3 = p3->next3;
}
printf(" ");
}
void toh(int n)
{
int i, x, a, b;
for (i = 0; i < (pow(2,n)); i++)
{
display1();
display2();
display3();
x = top_of_stack();
if (i % 2 == 0)
{
if (x == 1)
{
push3(pop1());
}
else if (x == 2)
{
push1(pop2());
}
else if (x == 3)
{
push2(pop3());
}
}
else
{
if (x == 1)
{
a = pop2();
b = pop3();
if (a < b && b != 999)
{
push3(b);
push3(a);
}
else if (a > b && a != 999)
{
push2(a);
push2(b);
}
else if (b == 999)
{
push3(a);
}
else if (a == 999)
{
push2(b);
}
}
else if (x == 2)
{
a = pop1();
b = pop3();
if (a < b && b != 999)
{
push3(b);
push3(a);
}
else if (a > b && a != 999)
{
push1(a);
push1(b);
}
else if (b == 999)
{
push3(a);
}
else if (a == 999)
{
push1(b);
}
}
else if (x == 3)
{
a = pop1();
b = pop2();
if (a < b && b != 999)
{
push2(b);
push2(a);
}
else if (a > b && a != 999)
{
push1(a);
push1(b);
}
else if (b == 999)
{
push2(a);
}
else if (a == 999)
{
push1(b);
}
}
}
}
}
int main()
{
int n, i;
printf("enter the number of plates : ");
scanf("%d",&n);
//push all plates to first stack
for (i = n; i >= 1; i--)
{
push1(i);
}
toh(n);
return 0;
}
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