Here's my code:
bigInt.cpp
/
// bigInt.cpp
#include "bigInt.h"
bigInt::bigInt() {
int i;
for(i = 0; i < SIZE; i++) //Sets all the values of digits to 0.
digits[i] = 0;
sign = true;
numDigits = 1;
error1 = true;
overflowFlag = false;
}
bigInt::bigInt(const char temp []) {
int i;
int tempSize = strlen(temp);
numDigits = 1;
error1 = true;
sign = true;
if(tempSize > 30)
error1 = false;
if(temp[0] == '-') { //If there's a negative symbol set the sign to false
sign = false;
if(tempSize > 31) //Add an extra space so the - doesn't count
error1 = false;
for(i = 0; i < SIZE; i++){
if(i < tempSize - 1)
if ( !(temp[tempSize-i - 1] >= 48 && temp[tempSize-i - 1] <= 58)){ //Check for errors
error1 = false;
}
else {
digits[i] = temp[tempSize-i-1] - '0';
if(digits[i]!=0)
numDigits = i+1;
}
else
digits[i] = 0;
}
}
else{
for(i = 0; i < SIZE; i++){
if(i < tempSize)
if ( !(temp[tempSize-i-1] >= 48 && temp[tempSize-i-1] <= 58)){ //Check for errors
error1 = false;
}
else {
digits[i] = temp[tempSize-i-1] - '0';
if(digits[i]!=0)
numDigits = i+1;
}
else
digits[i] = 0;
}
}
}
bigInt::bigInt(const string temp) {
int i;
int tempSize = temp.length();
numDigits = 1;
error1 = true;
sign = true;
if(tempSize > 30)
error1 = false;
if(temp[0] == '-') {//If there's a negative symbol set the sign to false
sign = false;
if(tempSize > 31)//Add an extra space so the - doesn't count
error1 = false;
for(i = 0; i < SIZE; i++){
if(i < tempSize - 1)
if ( !(temp[tempSize-i - 1] >= 48 && temp[tempSize-i - 1] <= 58)){ //Check for errors
error1 = false;
}
else {
digits[i] = temp[tempSize-i-1] - '0';
if(digits[i]!=0)
numDigits = i+1;
}
else
digits[i] = 0;
}
}
else{
for(i = 0; i < SIZE; i++){
if(i < tempSize)
if ( !(temp[tempSize-i-1] >=48 && temp[tempSize-i-1] <= 58) || temp[tempSize-i-1] == '-' ){//Check for errors
error1 = false;
if(sign == false)
error1 = true;
}
else {
digits[i] = temp[tempSize-i-1] - 48;
if(digits[i]!=0)
numDigits = i+1;
}
else
digits[i] = 0;
}
}
}
int bigInt::length() const {
return numDigits; //Returns the number of digits
}
bool bigInt::overflow() const {
return overflowFlag; //Overflow check
}
bool bigInt::error() const {
return !error1;//Error checking
}
bool bigInt::negative() const {
return !sign;//Sign checking
}
string bigInt::toString() const {
string output = "";
if(sign == false) //If there's a negative symbol it will be outputted
output = "-";
for(int i = numDigits - 1; i >= 0; i--) {
if ((i) % 3 == 2 && i < numDigits - 1)
output += ','; //Add commas
output += digits[i] + '0';
}
return output;
}
int bigInt::compare(const bigInt& x) const {
for(int i = SIZE - 1; i >= 0; i--){
if(sign == false && x.sign == true)
return -1;
else if(x.sign == false && sign == true)
return 1;
else if(sign == false && x.sign == false){
if(digits[i] > x.digits[i])
return -1;
else if(digits[i] < x.digits[i])
return 1;
}
else if(digits[i] < x.digits[i])
return -1;
else if(digits[i] > x.digits[i])
return 1;
}
return 0;
}
bigInt bigInt::add(const bigInt& x) const {
int carry = 0;
int i;
bigInt output;
for(i = 0; i < SIZE; i++) {
int value;
if(sign == false && x.sign == false)
output.sign = false;
value = digits[i] + x.digits[i] + carry;
carry = 0;
carry = value / 10;
output.digits[i] = value % 10;
if(value != 0)
output.numDigits = i + 1;
}
if (output.numDigits == SIZE && carry){
output.overflowFlag = true;
output.numDigits = 1;
for (i = 0; i < SIZE; i++) {
if(output.digits[i] != 0)
output.numDigits=i+1;
}
}
return output;
}
bigInt bigInt::sub(const bigInt& x) const {
int value;
int i;
bigInt output;
bigInt temp;
cout << "X num digits = " << x.numDigits << endl;
cout << "Num digits = " << numDigits << endl;
for(i = 0; i < SIZE; i++) {
if(sign == false && x.sign != false){
value = digits[i] + x.digits[i];
output.sign = false;}
else if(x.sign == false && sign != false)
value = digits[i] + x.digits[i];
else
if(digits[i] < x.digits[i]){
value = (digits[i] + 10) - x.digits[i];
output.digits[i] = value;
output.digits[i + 1] = digits[i + 1] -1;
}
else if(digits[i] >= x.digits[i]){
value = digits[i] - x.digits[i];
cout << "value" << value << endl;
output.digits[i] = value;}
if(value != 0)
output.numDigits = i + 1;
}
if (output.numDigits == SIZE){
output.overflowFlag = true;
output.numDigits = 1;
for (i = 0; i < SIZE; i++) {
if(output.digits[i] != 0)
output.numDigits=i+1;
}
}
return output;
}bigInt.h
#include <iostream>
#include <cstring>
#include <cmath>
#define SIZE 30
using namespace std;
class bigInt {
public:
bigInt();
bigInt(const char[]);
bigInt(const string);
int length() const;
bool overflow() const;
bool error() const;
bool negative() const;
string toString() const;
int compare(const bigInt&) const;
bigInt add(const bigInt&) const;
bigInt sub(const bigInt&) const;
private:
int digits[SIZE];
bool sign; //True for positive, false for negative.
bool error1;
int numDigits;
bool overflowFlag;
};main.cpp
#include "bigInt.h"
#include <iostream>
#include <iomanip>
using namespace std;
int main ()
{
bigInt a;
bigInt b;
bigInt c;
// Default Constructor & toString() Tests
cout << "a = " << a.toString() << endl;
cout << "b = " << b.toString() << endl;
cout << "c = " << b.toString() << endl;
cout << endl;
string userInput;
// Constructor Test (string w/ error checking)
cout << "Input a big int >" << endl;
cin >> userInput;
a = bigInt(userInput);
while(a.error()) {
cout << "Invalid input!" << endl;
cout << "Input a big int >" << endl;
cin >> userInput;
a = bigInt(userInput);
}
cout << endl;
// Constructor Test (char[] w/ error checking)
cout << "Input a big int >" << endl;
cin >> userInput;
b = bigInt( userInput.c_str() );
while(b.error()) {
cout << "Invalid input!" << endl;
cout << "Input a big int >" << endl;
cin >> userInput;
b = bigInt( userInput.c_str() );
}
cout << endl;
// Length Test
cout << setw((int)max(a.toString().length(), b.toString().length()));
cout << a.toString() << " has " << a.length() << " digits" << endl;
cout << setw((int)max(a.toString().length(), b.toString().length()));
cout << b.toString() << " has "<< b.length() << " digits" <<endl;
cout << endl;
// +/- Test
cout << setw((int)max(a.toString().length(),b.toString().length()));
cout << a.toString() << " is " << (a.negative()?"NEGATIVE":"POSITIVE") <<endl;
cout << setw((int)max(a.toString().length(),b.toString().length()));
cout << b.toString() << " is " << (b.negative()?"NEGATIVE":"POSITIVE") <<endl;
cout << endl;
// Comparison Test
if (a.compare(b) == 0)
cout << a.toString() << " == " << b.toString() << endl;
else if (a.compare(b) < 0)
cout << a.toString() << " < " << b.toString() << endl;
else
cout << a.toString() << " > " << b.toString() << endl;
cout << endl;
// Addition Test (w/ Overflow check)
c = a.add(b);
cout <<" " << setw(41) << a.toString() << endl;
cout <<"+" << setw(41) << b.toString() << endl;
cout << setfill('-') << setw(42) << "" << endl;
cout << setfill(' ');
cout << setw(42) << c.toString();
cout << (c.overflow()?" [OVERFLOW]":"") << endl;
cout << endl;
cout << endl;
// Subtraction Test (w/ Overflow check)
c = a.sub(b);
cout <<" " << setw(41) << a.toString() << endl;
cout <<"-" << setw(41) << b.toString() << endl;
cout << setfill('-') << setw(42) << "" << endl;
cout << setfill(' ');
cout << setw(42) << c.toString();
cout << (c.overflow()?" [OVERFLOW]":"") << endl;
cout << endl;
return 0;
}I'm having problems subtracting. My subtracting function is in the bigInt.cpp file at the very bottom. I have it so it should take away 1 from the left digit when the digit to the right is smaller than the one on the bottom but it doesn't seem to be working. The +10 works, but the borrowing part isn't.