Code:
package com.executecodes.numerical;
import java.util.Scanner;
public class BigNumber
{
static final int MAXDIGITS = 100; /* maximum length bignum */
static final int PLUS = 1; /* positive sign bit */
static final int MINUS = -1; /* negative sign bit */
char digits[]; /* represent the number */
int signbit; /* 1 if positive, -1 if negative */
int lastdigit; /* index of high-order digit */
BigNumber()
{
digits = new char[MAXDIGITS];
intToBigNumber(0);
}
void printBigNumber()
{
int i;
if (signbit == MINUS)
System.out.printf("- ");
for (i = lastdigit; i >= 0; i--)
System.out.printf("%c", '0' + digits[i]);
System.out.printf("\n");
}
void intToBigNumber(int s)
{
if (s >= 0)
signbit = PLUS;
else
signbit = MINUS;
for (int i = 0; i < MAXDIGITS; i++)
digits[i] = (char) 0;
lastdigit = -1;
int t = Math.abs(s);
while (t > 0)
{
lastdigit++;
digits[lastdigit] = (char) (t % 10);
t /= 10;
}
if (s == 0)
lastdigit = 0;
}
BigNumber addBigNumber(BigNumber b)
{
int carry, i;
BigNumber c = new BigNumber();
if (signbit == b.signbit)
c.signbit = signbit;
else
{
if (signbit == MINUS)
{
signbit = PLUS;
c = b.subtractBigNumber(this);
signbit = MINUS;
}
else
{
b.signbit = PLUS;
c = this.subtractBigNumber(b);
b.signbit = MINUS;
}
return c;
}
c.lastdigit = Math.max(lastdigit, b.lastdigit) + 1;
carry = 0;
for (i = 0; i <= c.lastdigit; i++)
{
c.digits[i] = (char) ((carry + digits[i] + b.digits[i]) % 10);
carry = (carry + digits[i] + b.digits[i]) / 10;
}
c.zeroJustify();
return c;
}
BigNumber subtractBigNumber(BigNumber b)
{
int borrow, v, i;
BigNumber c = new BigNumber();
if (signbit == MINUS || b.signbit == MINUS)
{
b.signbit = -b.signbit;
c = addBigNumber(b);
b.signbit = -b.signbit;
return c;
}
if (compareBigNumber(b) == PLUS)
{
c = b.subtractBigNumber(this);
c.signbit = MINUS;
return c;
}
c.lastdigit = Math.max(lastdigit, b.lastdigit);
borrow = 0;
for (i = 0; i <= c.lastdigit; i++)
{
v = digits[i] - borrow - b.digits[i];
if (digits[i] > 0)
borrow = 0;
if (v < 0)
{
v = v + 10;
borrow = 1;
}
c.digits[i] = (char) (v % 10);
}
c.zeroJustify();
return c;
}
int compareBigNumber(BigNumber b)
{
int i;
if (signbit == MINUS && b.signbit == PLUS)
return PLUS;
if (signbit == PLUS && b.signbit == MINUS)
return MINUS;
if (b.lastdigit > lastdigit)
return PLUS * signbit;
if (lastdigit > b.lastdigit)
return MINUS * signbit;
for (i = lastdigit; i >= 0; i--)
{
if (digits[i] > b.digits[i])
return MINUS * signbit;
if (b.digits[i] > digits[i])
return PLUS * signbit;
}
return 0;
}
void zeroJustify()
{
while (lastdigit > 0 && digits[lastdigit] == 0)
lastdigit--;
if (lastdigit == 0 && digits[0] == 0)
signbit = PLUS; /* hack to avoid -0 */
}
void digitShift(int d)
{
int i;
if (lastdigit == 0 && digits[0] == 0)
return;
for (i = lastdigit; i >= 0; i--)
digits[i + d] = digits[i];
for (i = 0; i < d; i++)
digits[i] = 0;
lastdigit += d;
}
BigNumber multiplyBigNumber(BigNumber b)
{
BigNumber row = new BigNumber();
BigNumber tmp = new BigNumber();
BigNumber c = new BigNumber();
int i, j;
row.signbit = this.signbit;
row.lastdigit = this.lastdigit;
System.arraycopy(this.digits, 0, row.digits, 0, this.digits.length);
for (i = 0; i <= b.lastdigit; i++)
{
for (j = 1; j <= b.digits[i]; j++)
{
tmp = c.addBigNumber(row);
c = tmp;
}
row.digitShift(1);
}
c.signbit = signbit * b.signbit;
c.zeroJustify();
return c;
}
BigNumber divideBigNumber(BigNumber b)
{
BigNumber row = new BigNumber();
BigNumber tmp = new BigNumber();
BigNumber c = new BigNumber();
int asign, bsign, i;
c.signbit = signbit * b.signbit;
asign = signbit;
bsign = b.signbit;
signbit = PLUS;
b.signbit = PLUS;
c.lastdigit = lastdigit;
for (i = lastdigit; i >= 0; i--)
{
row.digitShift(1);
row.digits[0] = digits[i];
c.digits[i] = 0;
while (row.compareBigNumber(b) != PLUS)
{
c.digits[i]++;
tmp = row.subtractBigNumber(b);
row = tmp;
}
}
c.zeroJustify();
signbit = asign;
b.signbit = bsign;
return c;
}
}
public class ArithmeticOpsBigNumbers
{
public static void main(String[] args)
{
int a, b;
BigNumber n1 = new BigNumber();
BigNumber n2 = new BigNumber();
BigNumber n3 = new BigNumber();
BigNumber zero = new BigNumber();
Scanner sc = new Scanner(System.in);
while (sc.hasNextInt())
{
a = sc.nextInt();
b = sc.nextInt();
System.out.printf("a = %d b = %d\n", a, b);
n1.intToBigNumber(a);
n2.intToBigNumber(b);
n3 = n1.addBigNumber(n2);
System.out.printf("Addition: ");
n3.printBigNumber();
System.out.printf("Comparing Numbers a ? b: %d\n",
n1.compareBigNumber(n2));
n3 = n1.subtractBigNumber(n2);
System.out.printf("Subtraction: ");
n3.printBigNumber();
n3 = n1.multiplyBigNumber(n2);
System.out.printf("Multiplication: ");
n3.printBigNumber();
zero.intToBigNumber(0);
if (zero.compareBigNumber(n2) == 0)
System.out.printf("Division: NaN \n");
else
{
n3 = n1.divideBigNumber(n2);
System.out.printf("Division: ");
n3.printBigNumber();
}
}
sc.close();
}
}
Output:
12342424
12313423
a = 12342424 b = 12313423
Addition: 24655847
Comparing Numbers a ? b: -1
Subtraction: 29001
Multiplication: 151977487557352
Division: 1
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