Operations on Big Numbers

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Ideas for storing and operating on Big numbers in C++ 

 

 Hello World!

Today I would like to share my C/C++ Code developed for storing and performing different operations on a Big Numbers. Big Numbers are those, which cannot handled by any normal predefined data type (int,float,double,long) of any available programming language.

I have developed that code to get big numbers and store them in user defined data type like linked list. Initially big number is stored in a String of chars. Doubly linked list is used store every single char per node.

Storing a big number in a linked list is just a one thing; there is no use of storing that number in linked list if you cannot perform different oppressions on it.

Therefore, I have developed this code in C language to perform very basic oppressions on it like divide and subtraction.

I have written this code last year. Until now, I did not update it. I know this code is not perfect but you still get basic idea from it. I think code is self explanatory

#include<iostream>
using namespace std;

typedef struct NodeType
{
	int data;
	struct NodeType *next;
	struct NodeType *prev;
}Node;

void createList(Node **head,Node **tail)
{
	*head=NULL;
	*tail=NULL;
}

void InsertNode(Node **head,Node **tail,int ele)
{
	Node *temp=(Node*)malloc(sizeof(Node));
	temp->data=ele;
	if(*head==NULL)
	{
		temp->next=NULL;
		temp->prev=NULL;
		*head=temp;
		*tail=temp;
	}
	else
	{
		temp->prev=*tail;
		temp->prev->next=temp;
		temp->next=NULL;
		*tail=temp;
	}
}

void InsertAtBeg(Node **head,Node **tail,int ele)
{
	Node *temp=(Node*)malloc(sizeof(Node));
	temp->data=ele;
	temp->prev=NULL;

	if(*head==NULL)
	{
		temp->next=NULL;
		*head=temp;
		*tail=temp;
	}
	else
	{
		temp->next=*head;
		*head=temp;
	}
		
}

void Subtract(Node *t1,Node *t2,Node **rh,Node **rt)
{
	if(t1==NULL && t2==NULL)
		printf("List t1 or t2 is NULL");
	else
	{
		while(t1!=NULL && t2!=NULL)
		{
			int a=t1->data;
			int b=t2->data;
			if(t1->data<t2->data)
			{
				a+=10;
				t1->prev->data-=1;
				Node *res=(Node*)malloc(sizeof(Node));
				int r=a-b;
				InsertNode(rh,rt,r);
			}
			else
			{
				int r=a-b;
				InsertNode(rh,rt,r);
			}
			t1=t1->prev;
			t2=t2->prev;
		}
		if(t1==NULL)
		{
			while(t2!=NULL)
			{
				InsertNode(rh,rt,t2->data);
				t2=t2->prev;
			}
		}
		else
		{
			while(t1!=NULL)
			{
				InsertNode(rh,rt,t1->data);
				t1=t1->prev;
			}
		}
	}
}

void divide(Node *t1,int div,Node **rh,Node **rt)
{
	int mod=0;

	if(t1==NULL)
		printf("List t1 is NULL");
	else
	{
		while(t1!=NULL)
		{
			int a=t1->data;
			if(t1->next!=NULL)
			{
				while(t1->data<div || t1->next->data==0)
				{
						a*=10;
						a+=t1->next->data;
						t1=t1->next;
						if(t1->next==NULL)
							break;
				}
			}

			{
				int r=a/div;
				mod=a%div;
				InsertNode(rh,rt,r);
			}
			t1=t1->next;
		}//while
		cout<<"Reminder:"<<mod;
	}
}

void display(Node *head,Node *tail,bool rev)
{
	if(head==NULL) return;
	else
	{
		if(rev==false)
		{
			Node *temp;
			temp=head;
			cout<<"Quotient:";
			while(temp!=NULL)
			{
				cout<<temp->data;
				temp=temp->next;
			}
			cout<<"\n";
		}
		else
		{
			Node *temp;
			temp=tail;
			while(temp!=NULL)
			{
				cout<<temp->data;
				temp=temp->prev;
			}
			cout<<"\n";
		}
	}
}

void convertStoI(Node **h1,Node **h2,Node **h3,Node **t1,Node **t2,Node **t3,bool flag)
{
	flushall();

	char F_no[10]; char S_no[10];
	cout<<"Enter First Value\n";
	cin.getline(F_no,10);
	int len1=strlen(F_no);
	for(int i=0;i<len1;i++)
	{
		InsertNode(h1,t1,F_no[i]-'0');
	}

	if(flag==true)// true means activate for subtract
	{
		cout<<"Enter Second Value\n";
		cin.getline(S_no,10);
		int len2=strlen(S_no);
		for(int i=0;i<len2;i++)
		{
			InsertNode(h2,t2,S_no[i]-'0');
		}
	}
}

void main()
{
	Node *h1,*t1;
	Node *h2,*t2;
	Node *h3,*t3;

	createList(&h1,&t1);
	createList(&h2,&t2);
	createList(&h3,&t3);
	
	int x=0;
	cout<<"Enter 1 for Subtraction:\n";
	cout<<"Enter 2 for Divide:\n";
	cin>>x;

		if(x==1)
		{
			convertStoI(&h1,&h2,&h3,&t1,&t2,&t3,true);
			Subtract(t1,t2,&h3,&t3);
			cout<<"\n";
			display(h3,t3,true);
		}
		else if(x==2)
		{
			convertStoI(&h1,&h2,&h3,&t1,&t2,&t3,false);
			int div=0;
			cout<<"Enter Dividend:";
			cin>>div;
			if(div!=0)
			{
				divide(h1,div,&h3,&t3);
				cout<<"\n";
				display(h3,t3,false);
			}
			else
				cout<<"Dividend should not be Zero(0)";
		}
			
	
}