ModAdd

input/code.cpp: In function 'int main()':
input/code.cpp:20:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while (i<=mystring.length()){
                             ^
input/code.cpp:25:33: error: variable-sized object 'out' may not be initialized
   int out[mystring.length()] = {};
                                 ^
input/code.cpp:27:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while (k<mystring.length()){
                            ^
input/code.cpp:33:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0; i< mystring.length(); i++){
                                   ^
input/code.cpp:43:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while (i<=mystring.length()){
                             ^
input/code.cpp:48:33: error: variable-sized object 'out' may not be initialized
   int out[mystring.length()...

#include <algorithm>
#include <stdio.h>
#include <iostream>
#include <string>
int main()
{
	using namespace std;
	ios::sync_with_stdio(0);
	string a,b;
	cin>>a;
	cin>>b;
	int diff;
	int length_a = a.length();
	int length_b = b.length();
	if (length_a>length_b){
		std::string mystring(length_a,'0');
		diff =  a.length() - b.length();
		int i = diff;
		int j = 0;
		while (i<=mystring.length()){
			mystring[i] = b[j];
			i+=1;
			j+=1;
		}
		int out[mystring.length()] = {};
		int k = 0;
		while (k<mystring.length()){
		
		out[k]=(int(a[k])-48)+(int(mystring[k])-48);
		out[k] = out[k]%10;
		k+=1;
		}
		for(int i=0; i< mystring.length(); i++){
			cout<<out[i];
		}
		
	}
	else if (length_a<length_b){
		std::string mystring(length_b,'0');
		diff =  b.length() - a.length();
		int i = diff;
		int j = 0;
		while (i<=mystring.length()){
			mystring[i] = a[j];
			i+=1;
			j+=1;
		}
		int out[mystring.length()] = {};
		int k = 0;
		while (k<mystring.length()){
		
		out[k]=(int(b[k])-48)+(int(mystring[k])-48);
		out[k] = out[k]%10;
		k+=1;
		}
		for(int i=0; i< mystring.length(); i++){
			cout<<out[i];
		}
		
		
	}
	else {
		int out[a.length()] = {};
		int k = 0;
		while (k<a.length()){
		
		out[k]=(int(b[k])-48)+(int(a[k])-48);
		out[k] = out[k]%10;
		k+=1;
		}
		for(int i=0; i< a.length(); i++){
			cout<<out[i];
		}
		
	}
	return 0;
}