Question

CS 211

Q.Adding BIG Integers In C++ an int is in the range 0 to 65535. But what if we need to add larger integers? Say we want to compute the sum 2345566777844567+ 9999988777765768009998. Your task in this assignment is to make this happen. Write a function string add(string a, string b)

Answer 1

Hi, Please find the solution, Explanations are inline.

//

// main.cpp

// HugeNumbersAdd

//

#include <iostream>

#include "string"

#include "algorithm"

using namespace std;

string add(string a, string b){

if(a.length()>b.length()){

string temp = a;

a=b;

b=temp;

}

string res = "";//empty for result

int len1 = a.length();

int len2 = b.length();

reverse(a.begin(), a.end());

reverse(b.begin(),b.end());

  

int carry = 0;

  

for (int i=0; i<len1; i++) {//adding until the size of the lower number

int sum = ((a[i]-'0')+(b[i]-'0')+carry);//-'0' is to convert char to number

res.push_back(sum%10+'0');

//carry for next step

carry = sum/10;

}

for(int i=len1;i<len2;i++){//this loop is after we are done with addition and if carry remains

int sum = ((b[i]-'0')+carry);

res.push_back(sum%10+'0');

carry = sum/10;

}

if(carry){//finally if carry remains

res.push_back(carry+'0');

}

reverse(res.begin(), res.end());//finally reversing

return res;

  

}

int main(int argc, const char * argv[]) {

string str1="122325",str2="45468";

cout<<"Enter big number 1:";

cin>>str1;

cout<<endl<<"Enter big number 2:";

cin>>str2;

cout<<add(str1, str2)<<endl;

}