Can you plz explain me with this?

content=//adding a new node at any place in a linked list


//acording to users choice





#include%26lt;iostream.h%26gt;


#include%26lt;conio.h%26gt;


#include%26lt;string.h%26gt;


#include%26lt;process.h%26gt;





struct abc


{


char n[20];


int p;


abc *next;


};


void main()


{


clrscr();


int c=0,per;


abc *list,*start=NULL,*ptr,*prev;


char nm[20],flag;


cout%26lt;%26lt;"enter the name and percentage marks of five children ";


for(int i=0;i%26lt;=4;i++)


{


if(start==NULL)


{


ptr=new abc;


cout%26lt;%26lt;"enter the details :";


cin%26gt;%26gt;ptr-%26gt;n%26gt;%26gt;ptr-%26gt;p;


start=ptr;


prev=ptr; //start=ptr=prev


}


else //implemented 4 times


{


ptr=new abc;





cin%26gt;%26gt;ptr-%26gt;n%26gt;%26gt;ptr-%26gt;p;


prev-%26gt;next=ptr;


prev=prev-%26gt;next;


}


}


int ch;


cout%26lt;%26lt;"\n enter the choice where the record is to be inserted \n";


cout%26lt;%26lt;"\n 1. starting of the list ";


cout%26lt;%26lt;"\n 2. in between ";


cout%26lt;%26lt;"\n 3. at the end";


cin%26gt;%26gt;ch;


list=new abc;


cout%26lt;%26lt;"\n enter the name and percent of new student :";


cin%26gt;%26gt;list-%26gt;n%26gt;%26gt;list-%26gt;p;


if (ch==1)


{


list-%26gt;next=start;


start=list;//now making list the starting point


}


else if(ch==3)


{


ptr=start;


while(ptr!=NULL)


{prev=ptr;


ptr=ptr-%26gt;next;


}


prev-%26gt;next=list;


list-%26gt;next=NULL;


}


else


{


cout%26lt;%26lt;"\n enter the record number (2-4) after which the node is to be inserted";


cin%26gt;%26gt;c;


if (c==1 || c==5)


{


cout%26lt;%26lt;"sorry wrong no. entered ";


exit(0);


}





i=0 ;


//insert the node


ptr=start;


cout%26lt;%26lt;"\n"%26lt;%26lt;"the list is :\n";


cout%26lt;%26lt;"name percentage\n";


while(ptr!=NULL)


{


i++;


if (i==c)


{


list-%26gt;next=ptr-%26gt;next; //????????


ptr-%26gt;next=list; //?????????????


}


ptr=ptr-%26gt;next;


}


}


ptr=start;


// display all the records ;


while (ptr!=NULL)


{


cout%26lt;%26lt;ptr-%26gt;n%26lt;%26lt;" "%26lt;%26lt;ptr-%26gt;p;


ptr=ptr-%26gt;next;


cout%26lt;%26lt;"\n";


}


getch();


}

Can you plz explain me with this?
list points to the new structure.


ptr points to the structure after which you will place list





so


list-%26gt;next = the next structure of where you are inserting list.


ptr-%26gt;next = list.





It basically places (list) in between ptr and ptr-%26gt;next.
Reply:Those two lines are simply moving some pointers. What exactly do you need explaining? Why do you need another example - surely the one you have is just fine?





I would recommend going and searching the net for C tutorials and references, and reading up on pointer operations. It might also be worth your time learning about linked lists and how they work.

survey