(not code just data)
10
1 123456789 987654321
2 9999999999 10000000000
2 10000000000 9999999999
1 3 5
2 7 7
2 0 5
1 19385838321938583832193858383219385838321938583832193858383219385838321938583832193858383219385838321938583832193858383200000000000000000000000000000000000000000000000000000000000000000000000000000000 95234567809123456780912345678091234567809123456780912345678091234567809123456780912345678091234567809123456780912345678091234567809123456780912345678091234567809123456780912345678091234567809123456780
2 19385838321938583832193858383219385838321938583832193858383219385838321938583832193858383219385838321938583832193858383200000000000000000000000000000000000000000000000000000000000000000000000000000000 95234567809123456780912345678091234567809123456780912345678091234567809123456780912345678091234567809123456780912345678091234567809123456780912345678091234567809123456780912345678091234567809123456780
2 23846098743650298740983098320576769760987394620943752836709832523980475208934750982365208743523 23846098743650298740983098320576769760987394620943752836709832523980475208934750982365208743523
1 935628126812131 148123782378218738287372

//John Torres
//COP 3223-0002
//Assignment #3
//Febuary, 20, 2009

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

struct integer* read_integer(char* stringInt);
struct integer* read_integerRec(char* stringInt, int len);
void print(struct integer *p);
void printRec(struct integer *p, int list_len);
struct integer* add(struct integer *p, struct integer *q);
struct integer* addRec(struct integer *p, struct integer *q, int carry);
struct integer* subtract(struct integer *p, struct integer *q);
struct integer* subtractRec(struct integer *p, struct integer *q, int barrow);
int compare(struct integer *p, struct integer *q);
int compareRec(struct integer* p, struct integer* q, int len);
void FreeList(struct integer *p);
struct integer* ResizeList(struct integer *p);
struct integer* ResizeListRec(struct integer *p, int len);
int ListSize(struct integer *p);

struct integer{
	int digit;
	struct integer *next;
};

int main(void)
{
    struct integer* head[3];
    char number[201];
    int file_len;
    int test1;
    int test2;
    int i,j;
    
    FILE *fin;
    
    //open file and get number of file lines
    fin = fopen("bigint.txt", "r");
    fscanf(fin, "%d", &file_len);

    //loop breaks after file is done
    for(i = 0; i < file_len; i++)
    {
        //read operation type, 1=add, 2=sub
        fscanf(fin,"%d", &test1);
        
        //reads the 2 strings and converts them to numbers
        for(j = 0; j < 2; j++)
        {
            fscanf(fin, "%s", number);
            head[j] = read_integer(number);
        }
        //if add
        if(test1 == 1)
        {
            //add function
            head[2] = add(head[0], head[1]);
            //resize
            head[2] = ResizeList(head[2]);
            
            //print operation
            print(head[0]);
            printf("\n+\n");
            print(head[1]);
            printf("\n=\n");
            print(head[2]);
            printf("\n\n");
            system("pause");
        }
        //if subtract
        else if(test1 == 2)
        {
            //subtract function
            head[2] = subtract(head[0], head[1]);
            //resize answer
            head[2] = ResizeList(head[2]);
            //check order
            test2 = compare(head[0], head[1]);
            
            //print operation
            if(test2 == -1)
            {//if second is larger
                print(head[1]);
                printf("\n-\n");
                print(head[0]);
                printf("\n=\n");
                print(head[2]);
                printf("\n");
                system("pause");
            }
            else
            {//if same or first is larger
                print(head[0]);
                printf("\n-\n");
                print(head[1]);
                printf("\n=\n");
                print(head[2]);
                printf("\n");
                system("pause");
            }
        }
        //if first number was not a 1 (add) or a 2 (sub)
        else
        {
            printf("BAD DATA");
        }
        
        //free lists
        FreeList(head[0]);
        FreeList(head[1]);
///////////////////////////////////////////////second problem 
///////////////////////////////////////////////dies here for just one line
        FreeList(head[2]);
    }
    
    return 0;
}

////////////////////////////////////////////////////////////////////////////////
//Preconditions:    the first parameter is string that stores
//                  only contains digits, doesn't start with
//                  0, and is 50 or fewer characters long.
//
//Postconditions:   The function will read the digits of the
//	                large integer character by character, 
//	                convert them into integers and place them in 
//	                nodes of a linked list. The pointer to the 
//	                head of the list is returned.
//
//Discription:      
////////////////////////////////////////////////////////////////////////////////
struct integer* read_integer(char* stringInt)
{
    struct integer* temp;
    int len;
    //find number of digits
    len = strlen(stringInt) - 1;
    //build struct
    return read_integerRec(stringInt, len);
}
struct integer* read_integerRec(char* stringInt, int len)
{
    struct integer* temp;
    //allocate memory
    temp = (struct integer*) malloc(sizeof(struct integer));
    //end case
    if(len == 0)
    {
        temp->digit = (int) stringInt[0] - '0';
        temp->next = NULL;
        return temp;
    }
    //base case
    else
    {
        temp->digit = (int) stringInt[len] - '0';
        temp->next = read_integerRec(stringInt, len-1);
        return temp;
    }
}

////////////////////////////////////////////////////////////////////////////////
//Preconditions:    p is a pointer to a big integer, stored in
//                  reverse order, least to most significant 
//                  digit, with no leading zeros.
//
//Postconditions:   The big integer pointed to by p is 
//                  printed out.
//
//Discription:      
////////////////////////////////////////////////////////////////////////////////
void print(struct integer *p)
{
    int list_len;
    //find list lenth
    list_len = ListSize(p);
    //print function
    printRec(p, list_len);
}
void printRec(struct integer *p, int list_len)
{
    struct integer* temp;
    int i;
    
    //end case
    if(list_len == 0)
    {
        printf("%d", p->digit);
    }
    //base case
    else
    {
        temp = p;
        
        //move pointer to end of list
        for(i = 0; i < list_len; i++)
        {
            temp = temp->next;
        }
        //print last number in list (first digit in number)
        printf("%d", temp->digit);
        
        //do it again
        printRec(p, list_len-1);
    }
}

////////////////////////////////////////////////////////////////////////////////
//Preconditions:    p and q are pointers to big integers, 
//                  stored in reverse order, least to most 
//                  significant digit, with no leading zeros.
//
//Postconditions:   A new big integer is created that stores
//                  the sum of the integers pointed to by p
//                  and q and a pointer to it is returned.
//
//Discription:      
////////////////////////////////////////////////////////////////////////////////
struct integer* add(struct integer *p, struct integer *q)
{
    return addRec(p, q, 0);
}
struct integer* addRec(struct integer *p, struct integer *q, int carry)
{
    struct integer* big_number;
    
    //allocate memory
    big_number = (struct integer*) malloc(sizeof(struct integer));
    
    //if nothing left to add
    if(q->next == NULL && p->next == NULL)
    {
        big_number->digit = p->digit + q->digit + carry;
        big_number->next = NULL;
        return big_number;
    }
    //if q is has no more numbers
    else if(q->next == NULL)
    {
        big_number->digit = q->digit+ p->digit + carry;
        big_number->next = p->next;
        return big_number;
    }
    //if p has no more numbers
    else if(p->next == NULL)
    {
        big_number->digit = p->digit + q->digit + carry;
        big_number->next = q->next;
        return big_number;
    }
    //base case
    else
    {
        //add
        big_number->digit = p->digit + q->digit + carry;
        
        //...carry the one...
        if(big_number->digit > 9)
        {
            big_number->digit -= 10;
            carry =1;
        }
        //reset carry
        else
        {
            carry = 0;
        }
        
        //do it again
        big_number->next = addRec(p->next, q->next, carry);
        return big_number;
    }
}

////////////////////////////////////////////////////////////////////////////////
//Preconditions:    p and q are pointers to big integers, 
//                  stored in reverse order, least to most 
//                  significant digit, with no leading zeros.
//
//Postconditions:   A new big integer is created that stores
//                  the absolute value of the difference 
//                  between the two and a pointer to this is
//                  returned.
//
//Discription:      
////////////////////////////////////////////////////////////////////////////////
struct integer* subtract(struct integer *p, struct integer *q)
{
    struct integer* big_number;
    int test;
    
    //compare list to find grater number
    test = compare(p, q);
    
    //if first is grater
    if(test == 1)
    {
        big_number = subtractRec(p, q, 0);
    }
    //if same or second is grater
    else
    {
        big_number = subtractRec(q, p, 0);
    }
    return big_number;
}
struct integer* subtractRec(struct integer *p, struct integer *q, int barrow)
{
    struct integer* big_number;
    
    //allocate memory
    big_number = (struct integer*) malloc(sizeof(struct integer));
    
    //if q has no more numbers after this one
    //and p is more then q + barrow
    //end case
    if(q->next == NULL && p->digit >= (q->digit + barrow))
    {
        big_number->digit = p->digit - q->digit - barrow;
        big_number->next = p->next;
        barrow = 0;
        return big_number;
    }
    //if q and p have no more numbers after this one
    //end case
    else if(q->next == NULL && p->next == NULL)
    {
        big_number->digit = p->digit - q->digit - barrow;
        big_number->next = NULL;
        barrow = 0;
        return big_number;
    }
    //if q has no more numbers after this one
    //and q + barrow is more then p
    //end case
    else if(q->next == NULL)
    {
        big_number->digit = p->digit - q->digit - barrow + 10;
        big_number->next->digit = p->next->digit - 1;
        big_number->next->next = p->next->next;
        barrow = 0;
        return big_number;
    }   
    //base case, p > q + barrow (dont need to barrow from next number
    else if(p->digit >= (q->digit + barrow))
    {
        big_number->digit = p->digit - q->digit - barrow;
        big_number->next = subtractRec(p->next, q->next, 0);
        return big_number;
    }
    //base case, p < q + barrow (need to barrow from next number
    else
    {
        big_number->digit = p->digit - q->digit - barrow + 10;
        big_number->next = subtractRec(p->next, q->next, 1);
        return big_number;
    }
}

////////////////////////////////////////////////////////////////////////////////
//Preconditions:    Both parameters of the function are 
//	                pointers to struct integer. 
//
//Postconditions:   The function compares the digits of two 
//	                numbers recursively and returns: 
//                      -1 if the first number is smaller than the second, 
//                      0 if the first number is equal to the second number,
//                      1 if the first number is greater than the second.
//
//Discription:      
////////////////////////////////////////////////////////////////////////////////
int compare(struct integer *p, struct integer *q)
{
    int p_len;
    int q_len;
    
    //finds number of digits in numbers
    p_len = ListSize(p);
    q_len = ListSize(q);
    
    //compares lenths
    if(p_len > q_len)
    {//p is longer
        return 1;
    }
    else if(p_len < q_len)
    {//q is longer
        return -1;
    }
    else
    {//need more info
        return compareRec(p, q, p_len);
    }
}
int compareRec(struct integer* p, struct integer* q, int len)
{
    struct integer* temp_p;
    struct integer* temp_q;
    int i;
    
    //assing temp pointers
    temp_p = p;
    temp_q = q;
    
    //end case
    if(len == 1)
    {
        //if p<q
        if(p->digit < q->digit)
        {
            return -1;
        }
        //if p>q
        else if(p->digit > q->digit)
        {
            return 1;
        }
        //if p=q
        else
        {
            return 0;
        }
    }
    //base case
    
    //move pointer to end of list (first number)
    for(i = 1; i < len; i++)
    {
        temp_p = temp_p->next;
        temp_q = temp_q->next;
    }
    //check
    //if p>q
    if(temp_p->digit > temp_q->digit)
    {
        return 1;
    }
    //if p<q
    else if(temp_p->digit < temp_q->digit)
    {
        return -1;
    }
    //need more info, do it again
    else
    {
        return compareRec(temp_p, temp_q, len-1);
    }
}

////////////////////////////////////////////////////////////////////////////////
//Preconditions:    A valid list header
//
//Postconditions:   All nodes in list are freed
//
//Discription:      
////////////////////////////////////////////////////////////////////////////////
void FreeList(struct integer *p)
{
    struct integer* temp;
    //base case
    if(p != NULL)
    {
        //temp point to 2nd node
        temp = p->next;
        //do it again
        FreeList(temp);
        //free first node
        free(p);
    }
    //end case (nothing...this is a void function)
}

////////////////////////////////////////////////////////////////////////////////
//Preconditions:    Valid list of numbers
//
//Postconditions:   returns a head pointer to a resied list. The new list has
//                  no ending zeros.
//
//Discription:      
////////////////////////////////////////////////////////////////////////////////
struct integer* ResizeList(struct integer *p)
{
    struct integer* temp;
    int len;
    
    //get list size (number of digits)
    len = ListSize(p);

    return ResizeListRec(p, len);
}
struct integer* ResizeListRec(struct integer *p, int len)
{
    struct integer* temp;
    int i;
    
    //keeps the last number, no matter what (even 0)
    //end case
    if(len == 1)
    {
        temp = p->next;
        p->next = NULL;
        free(temp);
        return p;
    }
    if(len == 0)
    {
        return p;
    }
    //assign temp
    temp = p;  

    //put temp to last node (first digit)
    for(i = 0; i < len - 1 ; i++)
    {
        temp = temp->next;
    }
    //check to see if digit is 0
    if(temp->next->digit == 0)
    {
//////////////////////////////////////first problem
//////////////////////////////////////Problem here after 5 calls on 3rd function
//////////////////////////////////////I think it is a memory issue
        //free usless node
        free(temp->next);
        //changes pointer to null (end of list)
        temp->next = NULL;
        //do it again
        return ResizeListRec(p, len - 1);
    }
    //if digit is not 0
    //end case
    else
    {
        return p;
    }
}

////////////////////////////////////////////////////////////////////////////////
//Preconditions:    Valid list of numbers
//
//Postconditions:   Returns an int the size of the number of nodes in the list
//
//Discription:      
////////////////////////////////////////////////////////////////////////////////
int ListSize(struct integer *p)
{
    struct integer* temp;
    int i;
    
    //assign temp
    temp = p;
    
    //count number of digits in list
    for(i = 0; temp->next != NULL; i++)
    {
        temp = temp->next;
    }
    return i;
}

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

int main() {
	void *ptr = malloc(666);
	free(ptr);
	puts("okay!");
	free(ptr);
	puts("okay!");
	return 0;
}

Computer Science I
Program 3: BigIntegers
Assigned: 2/9/09 (Monday)
Due: 2/20/09 (Friday 11:55pm over WebCT)
Note: For the Honors section, the program is due on 2/17/09.

The Problem
The unsigned int type in C requires 4 bytes of memory storage. With 4 bytes we can store integers as large as 232-1; but what if we need bigger integers, for example ones having hundreds of digits?  If we want to do arithmetic with such very large numbers we cannot simply use the unsigned data type. One way of dealing with this is to use a different storage structure for integers, such as linked lists. If we represent an integer as a linked list, we can represent very large integers, where each digit is a node in the list. Since the integers are allowed to be as large as we like, linked lists will prevent the possibility of overflows in representation. However we need new functions to add, subtract, read and write these very large integers.  

Write a program that will manipulate such arbitrarily large integers. Each integer should be represented as a linked list of digits. Your program will be required to read in big integers from a file, print big integers, and do addition or subtraction as required. 

Your program should store each decimal digit (0-9) in a separate node of the linked list. In order to perform addition and subtraction more easily, it is better to store the digits in the list in the reverse order. For instance, the value 1234567890 might be stored as:






Your program should include the following functions:

•	a function that will read in an integer from the keyboard
•	a function that will print an integer that is stored as a linked list.
•	a function that will add two integers represented as linked lists and returns a pointer to the resulting list.
•	a function that compares two integers and returns -1 if the first is less than the second, 0 if they are equal, and 1 if the first is greater than the second.
•	a function that will subtract one integer from the other and return a pointer to the resulting list. Since you’ll be dealing with positive integers only, the result should be a positive number. To ensure that the result is integer you should subtract the smaller number from the larger one (or equal). For this purpose you’re given a function that compares two large integers and returns –1, 0 or 1, depending on whether the first number is less than, equal to or greater than the second number.

 
Input/Output Specification
Your program should allow the user to do two things:

1) Add two big integers
2) Subtract to big integers

Instead of getting input from the user, you read in input from a file, "bigint.txt". (This will expedite the grading process.)

The input file format is as follows:

The first line will contain a single positive integer, n, representing the number of operations to carry out. The next n lines will contain one problem each. Each line will have three integers separated by white space. The first integer on each of these lines is guaranteed to either be 1 or 2, indicating addition and subtraction, respectively. The next two integers on the line will be the two operands for the problem. You may assume that these two integers are non-negative, are written with no leading zeros (unless the number itself is 0) and that the number of digits in either of the numbers will never exceed 200.

You should generate your output to the screen. In particular, you should generate one line of output per each input case. Your output should fit one of the two following formats:

X + Y = Z
X – Y = Z

corresponding to which option was chosen. For the first option, always print the first operand first. For the second option, always print the larger of the two operands first. If the two operands are equal, the same number is printed both times.

Implementation Restrictions
You must use the following struct:

struct integer{
	int digit;
	struct integer *next;
}

Whenever you store or return a big integer, always make sure not to return it with any leading zeros. Namely, make sure that the last node in the linked list returned does NOT store 0, unless the number stored is 0, in that case a single node should have 0 in it.

 
The prototypes for the functions you will write are below. You may include other functions, but it is required for these functions to be included.

//Preconditions: the first parameter is string that stores
//               only contains digits, doesn't start with
//               0, and is 50 or fewer characters long.
//Postconditions: The function will read the digits of the
//	large integer character by character, 
//	convert them into integers and place them in 
//	nodes of a linked list. The pointer to the //	head of the list is returned.
struct integer* read_integer(char* stringInt);

//Preconditions: p is a pointer to a big integer, stored in
//               reverse order, least to most significant 
//               digit, with no leading zeros.
//Postconditions: The big integer pointed to by p is 
//                printed out.
void print(struct integer *p);

//Preconditions: p and q are pointers to big integers, 
//               stored in reverse order, least to most 
//               significant digit, with no leading zeros.
//Postconditions: A new big integer is created that stores
//                the sum of the integers pointed to by p
//                and q and a pointer to it is returned.
struct integer* add(struct integer *p, struct integer *q);

//Preconditions: p and q are pointers to big integers, 
//               stored in reverse order, least to most 
//               significant digit, with no leading zeros.
//Postconditions: A new big integer is created that stores
//                the absolute value of the difference 
//                between the two and a pointer to this is
//                returned.
struct integer* subtract(struct integer *p, struct integer *q);

//Preconditions: Both parameters of the function are 
//	pointers to struct integer. 
//Postconditions: The function compares the digits of two 
//	numbers recursively and returns: 
//    -1 if the first number is smaller than the second, 
//     0 if the first number is equal to the second number,
//   1 if the first number is greater than the second.  
int compare(struct integer *p, struct integer *q);

 
Sample Input File
3
1 8888888888 2222222222
2 9999999999 10000000000
2 10000000000 9999999999

Corresponding Output
8888888888 + 2222222222 = 11111111110
10000000000 – 9999999999 = 1
10000000000 – 9999999999 = 1


Deliverables
Turn in a single file, bigintll.c, over WebCT that solves the specified problem. If you decide to make any enhancements to this program, clearly specify them in your header comment so the grader can test your program accordingly.