ds-lab/program8 at main · vampire-debug/ds-lab · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163

#include<stdio.h>
#include<stdlib.h>


struct node
{
int page;
struct node *left;
struct node *right;
};


typedef struct node *NODEPTR;
NODEPTR list=NULL;


NODEPTR createlist(NODEPTR list,int page);
NODEPTR moveforward(NODEPTR list, int cp ,int steps);
NODEPTR movebackward(NODEPTR list, int cp, int steps);
void display();
NODEPTR getnode();

NODEPTR createlist(NODEPTR list, int page)
{
	NODEPTR p,q;
	p=getnode();
	p->page=page;
	p->left=NULL;
	p->right=NULL;
	if(list==NULL)
		list=p;
	else{
		for(q=list; q->right!=NULL; q=q->right)
		;
		q->right=p;
		p->left=q;

	}
	return(list);
}


NODEPTR moveforward(NODEPTR list, int cp,int steps)
{
	NODEPTR p,q;
 	int count=0,s;
	if(list==NULL)
		printf("\n Empty list");
	else{
		p=list;
                for(p=list,count=0;count<cp-1; count++)
                  p=p->right;

                for(q=p,s=0;s<steps;s++)
                 {
                    if(q->right==NULL)
		    	return(q);
		    q=q->right;
 		   }
                 return(q);
}
}

NODEPTR movebackward(NODEPTR list, int cp,int steps)
{
	NODEPTR p,q;
 	int count=0,s;
	if(list==NULL)
		printf("\n Empty list");
	else{
		p=list;
                for(p=list,count=0;count<cp-1; count++)
                  p=p->right;

                for(q=p,s=0;s<steps;s++)
                 {
                    if(q->left==NULL)
		            	return(q);
		           q=q->left;
 		   }
                 return(q);
    }
}


void display(NODEPTR list)
{
	NODEPTR p;
	p=list;
	if(p==NULL)
		printf("\nEmpty list");
	else
	{
		printf("\n The page list contains: ");
		for(p=list;p!=NULL;p=p->right)
		{
			printf("%d<->",p->page);
		}
	}
}

NODEPTR getnode()
{
	NODEPTR r;
	r=(NODEPTR)malloc(sizeof(struct node));
	if(r==NULL)
	{
		printf("\n Node allocation failed");
		exit(0);
	}
	return(r);
}


void main()
{
		int page,choice,steps,cp;
 		char cont;
		NODEPTR p;
		do{
		printf("\n ...........MENU...........");
		printf("\n 1->CREATE LIST\t  2->MOVE FORWARD\t  3->MOVE BACKWARD\t 4->DISPLAY 5->EXIT");
		printf("\n Enter your choice");
		scanf("%d",&choice);
		switch(choice)
		{
		case 1:printf("\n CREATION OF DOUBLY LINKED LIST OF PAGES IS IN PROGRESS:\n");
			do{
              	        	  printf("Enter a page number:");
                        	  scanf("%d",&page);
              	 	 	  list = createlist(list,page);
              	 		  printf("Do you want to enter another page[Y/N]:");
               	 		  scanf(" %c",&cont);
              		 }while(cont=='Y' || cont=='y');
               		  display(list);
			  break;

		case 2: printf("\n MOVE FORWARD:\n");
			printf("\nEnter the current page:");
                        scanf("%d",&cp);
			printf("Enter the number of steps to move forward");
			scanf("%d",&steps);
			p=moveforward(list,cp,steps);
			printf("\n Moved forward to  page %d from %dth page",p->page, cp);
			break;
		case 3: printf("\n MOVE BACKWARD:\n");
			printf("\nEnter the current page:");
                        scanf("%d",&cp);
			printf("Enter the number of steps to move backward");
			scanf("%d",&steps);
			p=movebackward(list,cp,steps);
			printf("\n Moved backwards to  page %d from %dth page",p->page, cp);
			break;
		case 4: display(list);
		        break;
		case 5:printf("\n Quitting operation List.....\n");
			break;
		default:printf("\n Invalid choice");
			break;
		}
	}while(choice!=5);
}