TYBcs OS-Syspro Slip 11-1 | IProgramX

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

typedef struct node
{
char line[80];
struct node *next;
}NODE;

NODE *first,*last;
int len,changed;

NODE * get_node(char *s)
{
NODE *p;
p=(NODE*)malloc(sizeof(NODE));
strcpy(p->line,s);
p->next=NULL;
return p;
}

void create(char fname[])
{
NODE *p;
FILE *fp;
char buff[80];

fp = fopen(fname,"r");
if(fp==NULL)
{
printf("File %s not found.\n",fname);
exit(1);
}

while(fgets(buff,80,fp)!=NULL)
{
p = get_node(buff);

if(first==NULL)
first = p;
else
last->next = p;

last = p;
len++;
}

fclose(fp);
}

void append()
{
NODE *p;
char buff[80];

printf("Enter text (type END to stop):");

fflush(stdin);
fgets(buff,80,stdin);

while(strcmp(buff,"END\n")!=0)
{
p = get_node(buff);
if(first==NULL)
first = p;
else
last->next = p;
last=p;
len++;

fflush(stdin);
fgets(buff,80,stdin);
}

changed=1;
}

void insert(int pos)
{
NODE *first1=NULL,*last1,*p,*q;
int i=0;
char buff[80];

printf("Enter text to insert (type END to stop):");

fflush(stdin);
fgets(buff,80,stdin);

while(strcmp(buff,"END\n")!=0)
{
p = get_node(buff);
if(first1==NULL)
first1=p;
else
last1->next=p;
last1=p;
i++;

fflush(stdin);
fgets(buff,80,stdin);
}
len+=i;
p = q = first;
i=1;
while(i<pos)
{
i++;
q=p;
p=p->next;
}

if(p==first)
{
last1->next=first;
first=first1;
}
else
{
q->next=first1;
last1->next=p;
}

changed=1;
}

void print(int n1, int n2)
{
int i;
NODE *p;

i=1;
p=first;
while(i<n1)
{
i++;
p=p->next;
}

i=n1;
while(i<=n2)
{
printf("%d: %s",i,p->line);
i++;
p=p->next;
}
}

int main(int argc, char *argv[])
{
char buff[80],ch,fname[30]="";
int n1,n2;

if(argc==2)
{
strcpy(fname,argv[1]);
create(fname);
}

while(1)
{
printf("$");
fflush(stdin);
fgets(buff,80,stdin);

sscanf(buff,"%c %d %d",&ch,&n1,&n2);

switch(ch)
{
case 'a':
append();
break;
case 'p':
if(n1>=1 && n2<=len && n1<=n2)
print(n1,n2);
else
printf("Invalid parameter\n");
break;
case 'i':
if(n1>=1 && n1<=len)
insert(n1);
else
printf("Invalid parameter\n");
break;
case 'e':
exit(0);
default:
printf("Invalid command.\n");
}
}

return 0;
}