C :

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int x[1001],y[1001],z[1001];
int main(){
	char a[1001],b[1001];
	scanf("%s%s",&a,&b);
	//strcmp(a,b) 判断两个字符串是否相等,相等则为0 
	if(strcmp(a,"0")==0){
		printf("%s",b);
		return 0;
	}else if(strcmp(b,"0")==0){
		printf("%s",a);
		return 0;
	}
	int alen = strlen(a); 
	int blen = strlen(b);
	int i,k=0,p=0;
	for(i=alen-1;i>=0;i--){
		x[k]  = a[i]-'0';
		k++;
	}
	for(i=blen-1;i>=0;i--){
		y[p]  = b[i]-'0';
		p++;
	}
	int n = alen;
	if(n<blen)  n= blen;
	int f = 0;
	for(i=0;i<n;i++){
		z[i] = x[i] + y[i] + f;
		if(z[i]>=10){	
			f = 1;
		}else{
			f = 0;
		}
		z[i] = z[i]%10;
	}
	if(f==1) z[i] = 1;
	int j = n;
	for(i=n;i>=0;i--){
		if(z[i]!=0){
			j = i;
			break;
		}
	}
	for(i=j;i>=0;i--){
		printf("%d",z[i]);
	}
	return 0;
}

C++ :

#include <bits/stdc++.h>
using namespace std;

int main(){
	
	//开始编写程序
	string s1,s2;//s1 s2代表2个要运算的数
	//数组定义时不赋值，值是未知数，如果定义的时候赋值，但赋值元素个数不够，默认补充0
	//用这个特性初始化数组都为0 
	int a[250] = {0},b[250] = {0},r[250] = {0}; 
	int len,i,j;
	getline(cin,s1); 
	getline(cin,s2);
	//得到较长的字符串的长度，按照这个长度运算，短的要在前面补0（相当于倒过来后面补0） 
	len = s1.length() > s2.length()?s1.length():s2.length();
	 
	//倒过来将字符串存入数组再运算，注意字符要转化为实际的整数
	for(i = 0;i < s1.length();i++){
		a[i] = s1[s1.length() - i - 1] - 48;
	} 
	
	for(i = 0;i < s2.length();i++){
		b[i] = s2[s2.length() - i - 1] - 48;
	} 
	
	//a b数组按照较长的长度，逐位运算
	for(i = 0;i < len;i++){
		r[i] = a[i] + b[i];
	} 
	
	//r数组逐位进位 
	for(i = 0;i < len;i++){
		r[i + 1] = r[i + 1] + r[i] / 10; 
		r[i] = r[i] % 10;
	} 
	
	//倒过来从第一个非0开始输出r数组
	//r数组的长度最多是len + 1
	if(r[len] != 0) len++;
	for(i = len - 1;i >= 0;i--) {
		cout<<r[i];
	}
}

Pascal :

var
  s1,s2:string;
  a,b:array[1..10000] of longint;
  i,j,k,ii,jj:longint;
begin
  readln(s1);
  readln(s2);
  ii:=length(s1);
  jj:=length(s2);
  if ii>jj then j:=ii
           else j:=jj;
  k:=0;
  for i:=ii downto 1 do
  begin
    k:=k+1;
    a[k]:=ord(s1[i])-ord('0');
  end;
  k:=0;
  for i:=jj downto 1 do
  begin
    k:=k+1;
    b[k]:=ord(s2[i])-ord('0');
  end;
  for i:=1 to j do
  begin
    a[i]:=a[i]+b[i];
    if a[i]>10 then begin
 		      a[i]:=a[i]-10;
		      a[i+1]:=a[i+1]+1;
		    end;
  end;
  if a[i+1]=0 then j:=j-1;
  for i:=j+1 downto 1 do write(a[i]);
end.

Java :

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;


public class Main {
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		String[] st1=sc.nextLine().split("");
		String[] st2=sc.nextLine().split("");
		List<Integer> s1=new ArrayList<Integer>();
		List<Integer> s2=new ArrayList<Integer>();
		for(int i=st1.length-1;i>=0;i--){
			if(!st1[i].equals("")){
				s1.add(Integer.parseInt(st1[i]));
			}
		}
		for(int i=st2.length-1;i>=0;i--){
			if(!st2[i].equals("")){
				s2.add(Integer.parseInt(st2[i]));
			}
		}
		if(s1.size()>=s2.size()){
			for(int i=0;i<s2.size();i++){
				s1.set(i, s1.get(i)+s2.get(i));
			}
			for(int i=0;i<s1.size()-1;i++){
				int n1=s1.get(i);
				int n2=s1.get(i+1);
				if(n1>=10){
					s1.set(i, n1-10);
					s1.set(i+1, n2+1);
				}
			}
			if(s1.get(s1.size()-1)>=10){
				s1.set(s1.size()-1, s1.get(s1.size()-1)-10);
				s1.add(1);
			}
			for(int i=s1.size()-1;i>=0;i--){
				System.out.print(s1.get(i));
			}
		}else{
			for(int i=0;i<s1.size();i++){
				s2.set(i, s1.get(i)+s2.get(i));
			}
			for(int i=0;i<s2.size()-1;i++){
				int n1=s2.get(i);
				int n2=s2.get(i+1);
				if(n1>=10){
					s2.set(i, n1-10);
					s2.set(i+1, n2+1);
				}
			}
			if(s2.get(s2.size()-1)>=10){
				s2.set(s2.size()-1, s2.get(s2.size()-1)-10);
				s2.add(1);
			}
			for(int i=s2.size()-1;i>=0;i--){
				System.out.print(s2.get(i));
			}
		}
	}
}

Python :

print(int(input())+int(input()))