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2007-11-01T22:06:32Z

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<pre>
#include <iostream>
#include <fstream>
#include <string>
using namespace std;

const int MAX = 5/*0*/;

struct BigInt
{
int Digits[MAX];
int numDigits;
};

bool ReadBigInt(BigInt& num);
//Purpose:Read a BigInt, deposit into a string and convert from characters to numeric data
//Precondition:None.
//Postcondition:1.Array is populated, data is valid.
// 2.BigInt is too large, loops until an Int is entered that is small enough.
void PrintBigInt(const BigInt& num);
//Purpose:Print a BigInt in the same way it was entered by reversing the way it was stored into the array.
//Precondition:BigInt num is valid.
//Postcondition:Data is printed on screen matching the way it was entered from the console.
bool AddBigInts(const BigInt& num1, const BigInt& num2, BigInt& sum);
//Purpose:Add two integers together into a sum.
//Precondition:BigInts num1 and num2 are valid.
//Postcondition:1.Return true if sum is valid.
// 2.Return false if there is overflow.
void firstIntegerLarger(const BigInt& largest, const BigInt& smallest, BigInt& sum);
//Purpose:Modularize AddBigInts function to make it more efficent.
//Precondition:BigInts num1 and num2 have been entered and contain good data.
//Postcondition:1.Sum has been populated by good data as long as num.numDigits <= MAX.
// 2.If there is overflow (num.numDigits > MAX) it will be indicated in AddBigInts.

void main()
{
BigInt x,y,sum;
bool moreNumbers = true;
char update = ' ';

while(moreNumbers)
{
ReadBigInt(x);
ReadBigInt(y);
cout<<"The BigInt entered is: ";
PrintBigInt(x);
cout<<"The BigInt entered is: ";
PrintBigInt(y);
AddBigInts(x,y,sum);
cout<<"The sum is: ";
PrintBigInt(sum);

cout<<"Do you want to add more numbers? (Y or N): ";
cin>>update;
cin.ignore(50,'\n');
cout<<"==========================================="<<endl;

if(update == 'Y' || update == 'y')
{
moreNumbers = true;
}
else
{
moreNumbers = false;
}
}
cout<<"Program Terminated on request."<<endl;
}

bool ReadBigInt(BigInt& num)
{
int len = 0;
char ch = ' ';
int counter = 0;
bool tooBig = false;
string str = "";

while(!tooBig) //Initialize tooBig, if integer is too big loop until BigInt entered is valid.
{
cout<<"Enter an integer: ";
getline(cin,str);

len = (int)str.length(); //Length of the string entered into len

if (len > MAX)
{
cout<<"The number you entered is too big, try again!"<<endl;
tooBig = false;
}
else
{
num.numDigits = len;

for(int i = len-1; i >= 0; i--) //Reverse the string and position of numbers
{
ch = str[i]; //Convert from char to numeric value
num.Digits[counter] = ch - '0'; //char c = '2';
counter++; //int n = c - '0';
}
tooBig = true;
}
}
return true;
}

void PrintBigInt(const BigInt& num)
{
int counter = num.numDigits - 1;

if(num.numDigits > MAX)
{
cout<<"OVERFLOW";
}
else
{
for(int i = 0; i < num.numDigits; i++)
{
cout<<num.Digits[counter];
counter--;
}
}
cout<<endl;
}

bool AddBigInts(const BigInt& num1, const BigInt& num2, BigInt& sum)
{
if(num1.numDigits >= num2.numDigits)
{
firstIntegerLarger(num1, num2, sum);
}
else
{
firstIntegerLarger(num2, num1, sum);
}

//If Overflow return false, otherwise return true
if(sum.numDigits > MAX)
{
return false;
}
else
{
return true;
}
}

void firstIntegerLarger(const BigInt& largest, const BigInt& smallest, BigInt& sum)
{
int i;
int remainder = 0;

for(i = 0; i < smallest.numDigits; i++)
{
sum.Digits[i] = largest.Digits[i] + smallest.Digits[i] + remainder;

if(sum.Digits[i] >= 10)
{
sum.Digits[i] = (sum.Digits[i] - 10);
remainder = 1;
}
else
{
remainder = 0;
}
}

for(; i < largest.numDigits; i++)
{
sum.Digits[i] = largest.Digits[i] + remainder;

if(sum.Digits[i] >= 10)
{
sum.Digits[i] = (sum.Digits[i] - 10);
remainder = 1;
}
else
{
remainder = 0;
}
}

if(i == largest.numDigits && remainder == 1)
{
sum.Digits[i] = 1;
sum.numDigits = largest.numDigits + 1;
}
else
{
sum.numDigits = largest.numDigits;
}
}
</pre>

Directory:Derek Elder/Programs/ReadBigInt - Revision history

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