Realize a large bit number phase multiplication algorithm

Implement a function of a computational large bit number (such as more than 100 digits) multiplied results (please completely use algorithm)

#include

#include

#include

Multiply (char * a_strmultp1, char * a_STRMULTP2)

{

INT LEN1; // the length of multiplier1

INT LEN2; // the length of multiplier2

LEN1 = Strlen (a_strmultp1);

Len2 = Strlen (a_strmultp2);

Char * strret = new char (iMULTP1LEN IMULTP2LEN); // the result;

MEMSET (Strret, '0', Imultp1len Imultp21);

// if Either's length is 0, the meaning;

IF (len1 <= 0 || LEN 2 <= 0)

{

COUT << "error" << endl;

exit (0);

}

INT I;

Int J;

IC Icarry; // the carry;

Int idigit; // the Digit;

Icarry = 0;

iDigit = 0;

Int Len;

INT TEMP = 0;

For (i = len2-1; i> = 0; i -)

{

For (j = len1-1; j> = 0; J -)

{INT JJ = LEN2 LEN1-J-I-2;

IDIGIT = (A_StrMultp2 [i] - '0') * (a_strmultp1 [j] - '0') iCarry;

Icarry = iDigit / 10;

iDigit = iDigit% 10;

Temp = Strret [JJ] - '0' iDigit;

IF (TEMP / 10)

Icarry = Icarry TEMP / 10;

Strret [JJ] = TEMP% 10 '0';

Icarry

Strret [JJ 1] = ICARRY% 10 Strret [JJ 1];

Icarry = Icarry / 10;

}

}

Icarry

{

Strret [len2 len1-1] = iCarry '0';

Len = len2 len1-1;

}

Else

Len = len2 len1-2;

For (i = le; i> = 0; i -)

Cout << Strret [I];

Cout << Endl;

}

Main ()

{

MULTIPLY ("177856", "196196");

}