这段程序输出55,为什么
#include<iostream>
#include<cstdio>#include<cstring>#include<string>using namespace std;struct intint{string s;int a[20000];int len;};intint plus(intint a,intint b){intint c;c.len=1;a.len=a.s.length(),b.len=b.s.length();for(int i=0;i<=a.len-1;++i)a.a[a.len-i]=a.s[i]-48;//反序for(int i=0;i<=b.len-1;++i)b.a[b.len-i]=b.s[i]-48;int x=0;while(c.len<=a.len||c.len<=b.len){c.a[c.len]=b.a[c.len]+a.a[c.len]+x;x=c.a[c.len]%10;c.a[c.len]%=10;c.len++;}c.a[c.len]=x;if(c.a[c.len]==0)c.len--;return c;}int main(){return 0;}