CodePudding user response:

 # include & lt; Iostream> 
#include  
using namespace std; 
The inline int the compare (string str1, string str2) {//return equal 0, is greater than the return 1, less than the return 1 
If (str1. The size () & gt; Str2. The size ()) return 1;//the length of the long integer greater than the length of the integer 
Else if (str1. The size () & lt; Str2. The size ()) return 1; 
The else pare said return str1.com (str2);//if equal length, head to tail according to the comparison of 
} 
String SUB_INT (string str1, string str2); 
String ADD_INT (string str1, string str2) {//high precision addition 
Int sign=1;//sign for the sign bit 
String STR. 
If (str1 [0]=='-') {
If (str2 [0]=='-') {
Sign=1; 
STR=ADD_INT (str1. Erase (0, 1), str2. Erase (0, 1)); 
} else {
STR=SUB_INT (str2, str1. Erase (0, 1)); 
} 
} else {
If (str2 [0]=='-') {
STR=SUB_INT (str1, str2. Erase (0, 1)); 
} else {//alignment, the two integers up short integer adding 0 
String: : size_type L1, L2, 
int i; 
L1=str1. The size (); 
L2=str2. The size (); 
If (L1 & lt; L2) {
For (I=1; i<=L2 - L1. I++) str1="0" + str1; 
} else {
For (I=1; i<=L1, L2, I++) str2="0" + str2; 
} 
Int int1=0, int2=0;//record int2 carry 
For (I=str1. The size () - 1; I>=0; I -) {
Int1=(int (str1 [I]) - '0' + int (str2 [I]) - '0' + int2) % 10; 
Int2=(int (str1 [I]) - '0' + int (str2 [I]) - '0' + int2)/10; 
STR=char (int1 + '0') + STR. 
} 
If (int2! STR==0) char (int2 + '0') + STR; 
} 
} 
//operation post-processing the sign bit 
If ((sign==1) & amp; & (STR [0]! STR='0'))="-" + STR; 
return str; 
} 
String SUB_INT (string str1, string str2) {//high precision subtraction 
Int sign=1;//sign for the sign bit 
String STR. 
int i,j; 
If (str2 [0]=='-') {
STR=ADD_INT (str1, str2. Erase (0, 1)); 
} else {
Int res=compare (str1, str2); 
If (res==0) return "0". 
If (res<0 {
Sign=1; 
String temp=str1; 
Str1=str2; 
Str2=temp; 
} 
String: : size_type tempint; 
Tempint=str1. The size () - str2. The size (); 
For (I=str2. The size () - 1; I>=0; I -) {
If (str1 + tempint [I] j=1; 
While (1) {//zhao4zhong1 add 
If (str1 [I + tempint - j]=='0') {
Str1 [I + tempint - j]='9'; 
j++; 
} else {
Str1 [I + tempint - j]=char (int (str1 [I + tempint - j]) - 1); 
break; 
} 
} 
STR=char (str1 + tempint [I] - str2 [I] + ':') + STR. 
} else {
STR=char (str1 + tempint [I] - str2 [I] + '0') + STR. 
} 
} 
For (I=tempint - 1; I>=0; I -) STR=str1 [I] + STR; 
} 
//remove the excess of leading 0 
STR. Erase (0, STR. Find_first_not_of (' 0 ')); 
If (STR) empty ()) STR="0"; 
If ((sign==1) & amp; & (STR [0]! STR='0'))="-" + STR; 
return str; 
} 
String MUL_INT (string str1, string str2) {//high precision multiplication 
Int sign=1;//sign for the sign bit 
String STR. 
If (str1 [0]=='-') {
Sign *=1; 
Str1=str1. Erase (0, 1); 
} 
If (str2 [0]=='-') {
Sign *=1; 
Str2=str2. Erase (0, 1); 
} 
int i,j; 
String: : size_type L1, L2, 
L1=str1. The size (); 
L2=str2. The size (); 
For (I=L2-1; I>=0; I -) {//analog multiplication by hand upright 
String tempstr; 
Int int1=0, int2=0, int3=int (str2 [I]) - '0'. 
If (int3!=0) {
For (j=1; j<=(int) (L2-1 - I); J++) tempstr="0" + tempstr; 
For (j=L1-1; J>=0; J -) {
Int1=(int3 * (int (str1 [j]) - '0') + int2) % 10; 
Int2=(int3 * (int (str1 [j]) - '0') + int2)/10; 
Tempstr=char (int1 + '0') + tempstr; 
} 
If (int2! Tempstr==0) char (int2 + '0') + tempstr; 
} 
STR=ADD_INT (STR, tempstr); 
} 
//remove the results of the leading 0 
STR. Erase (0, STR. Find_first_not_of (' 0 ')); 
If (STR) empty ()) STR="0"; 
If ((sign==1) & amp; & (STR [0]! STR='0'))="-" + STR; 
return str; 
} 
String str2 string DIVIDE_INT (string str1, int flag) {//high precision division, the flag==1, return to business; Flag==0, return to the remainder 
String quotient, residue;//define the quotient and remainder 
Int sign1=1, sign2=1; 
If (str2=="0") {//whether divisor of 0 
Quotient="ERROR!" ; 
Residue="ERROR!" ; 
If (flag==1) return quotient; 
The else return residue; 
} 
If (str1=="0") {//whether the dividend of 0 
Quotient="0"; 
Residue="0"; 
} 
If (str1 [0]=='-') {
Str1=str1. Erase (0, 1); 
Sign1 *=1; 
Sign2=1; 
} 
If (str2 [0]=='-') {
Str2=str2. Erase (0, 1); 
Sign1 *=1; 
} 
Int res=compare (str1, str2); 
If (res<0 {
Quotient="0"; 
Residue=str1; 
{} else if (res==0) 
Quotient="1"; 
Residue="0"; 
} else {
String: : size_type L1, L2, 
L1=str1. The size (); 
L2=str2. The size (); 
String tempstr; 
nullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnull