Question

Write a program to subtract large unsigned integers. Your program should prompt and read in two large unsigned integers. The two large integers should be stored arrays, one array for each integer. The integers should be stored with one digit per location in the two arrays. The first integer should be no smaller than the second. Your program should subtract the second integer from the first. The result should be stored in an array, again one digit per location in the array. Your program should then output the difference, there should be no leading zeros. Your program should be able to handle integers with up to 80 digits each. You should not use any concepts from object oriented programming. In particular please do not use any classes (or struct) or any class methods. The one exception is that you may use cin, cout and the iostream class method cin.get(). Test data:

10000000000000000000000000000000000

- 9

1111111111111111111111111111111111

- 10000010001

123456789123456789123456789

- 99999

9999999999

- 9999999999

IN C++ PROGRAMMING LANGUAGE PLEASE

Answer 1

Code in C++ (used strings instead of arrays because the input would become simple)

#include<bits/stdc++.h>

using namespace std;

// Returns true if str1 is smaller than str2.

bool isSmaller(string str1, string str2) {

    // Calculate lengths of both string

    int n1 = str1.length(), n2 = str2.length();

    if (n1 < n2)

    return true;

    if (n2 < n1)

    return false;

    for (int i=0; i<n1; i++)

    if (str1[i] < str2[i])

        return true;

    else if (str1[i] > str2[i])

        return false;

    return false;

}

string findDiff(string str1, string str2){

    // Before proceeding further, make sure str1

    // is not smaller

    if (isSmaller(str1, str2))

        swap(str1, str2);

    // Take an empty string for storing result

    string str = "";

    // Calculate length of both string

    int n1 = str1.length(), n2 = str2.length();

    // Reverse both of strings

    reverse(str1.begin(), str1.end());

    reverse(str2.begin(), str2.end());

    

    int carry = 0;

    // Run loop till small string length

    // and subtract digit of str1 to str2

    for (int i=0; i<n2; i++)

    {

        // Do school mathematics, compute difference of

        // current digits

        

        int sub = ((str1[i]-'0')-(str2[i]-'0')-carry);

        

        // If subtraction is less then zero

        // we add then we add 10 into sub and

        // take carry as 1 for calculating next step

        if (sub < 0)

        {

            sub = sub + 10;

            carry = 1;

        }

        else

            carry = 0;

        str.push_back(sub + '0');

    }

    // subtract remaining digits of larger number

    for (int i=n2; i<n1; i++)

    {

        int sub = ((str1[i]-'0') - carry);

        

        // if the sub value is -ve, then make it positive

        if (sub < 0)

        {

            sub = sub + 10;

            carry = 1;

        }

        else

            carry = 0;

            

        str.push_back(sub + '0');

    }

    // reverse resultant string

    reverse(str.begin(), str.end());

    return str;

}

// Driver code

int main()

{

    cout<<"Enter two unsigned integer: \n";

    string str1 = "10000000000000000000000000000000000";

    string str2 = "9";

    cin>>str1>>str2;

    cout<<"Difference = "<<findDiff(str1,str2);

    

    return 0;

}