Java program to multiply large numbers has been shown here. This program follows the standard multiplication algorithm.

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1. Program & Output

## 1. Java program & output to Multiply Large numbers

Code has been copied
/***************************************
alphabetacoder.com
Java program to multiply large numbers
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import java.util.Scanner;

class Main {
public static void main(String args[]) {
// declare instance of Scanner class
Scanner sc = new Scanner(System.in);

// declare varables
char[] num1 = new char[500]; // for storing first numbers.
char[] num2 = new char[500]; // for storing second numbers.
int[] result = new int[1000]; // for storing the result
int n1, n2, d1, d2, i, j, sum, carry, flag = 0;

System.out.print("Enter the first number: ");
num1 = sc.next().toCharArray();
System.out.print("Enter the second number: ");
num2 = sc.next().toCharArray();

//find the number of digits for both numbers.
n1 = num1.length;
n2 = num2.length;

// Perform multiplication
// Multiply each digit of num1 with each digit of num2
for (i = n1 - 1; i >= 0; i--) {
// initialize
carry = 0;
d1 = num1[i] - '0'; // current digit of first number

for (j = n2 - 1; j >= 0; j--) {
d2 = num2[j] - '0'; // current digit of second number
// calculate sum
sum = d1 * d2 + result[i + j + 1] + carry;
result[i + j + 1] = sum % 10;
// calculate carry
carry = sum / 10;
}

// Set the carry to the leading digit
result[i] = carry;
}

// display the result
System.out.print("Result = ");
for (i = 0; i < (n1 + n2); i++) {
if (result[i] != 0)
flag = 1;
if (flag == 1)
System.out.print(result[i] + "");
}
}
}


Output

Enter the first number: 95645321827654784646846744467874574999555664226577

Enter the second number: 57454545445787798756998862211360065474755258565

Result = 5495258489623991547912527139389052273835545445473793418196901198146636507325023577503884379882005