题解 | #高精度整数加法#

#include <algorithm>
#include <iostream>
#include <string>
using namespace std;

int main() {
    string str1,str2;
    cin>>str1>>str2;
    int m=str1.size(),n=str2.size();
    int sum=0;
    int carry=0;//进位
    string ans="";
    int i=m-1,j=n-1;
    while(i>=0 || j>=0)
    {
        int num1,num2;
	  //判断字符串是否还有字符
        num1 = (i>=0) ? (str1[i]-'0') : 0;
        num2 = (j>=0) ? (str2[j]-'0') : 0;
        sum = num1 + num2+carry;
        carry =sum /10;//进位
        ans+=(sum % 10)+'0';  
        i--;
        j--;
    }
    if(carry != 0)
        ans+= to_string(carry);
    reverse(ans.begin(), ans.end());
    cout<<ans<<endl;
    return 0;

}