1.如果用string接收一串数字那必须加双引号”“
,否则会出现乱码:

2.但是如果用cin,然后用户直接输入一串数字,不用加双引号也没事,如s。
#include <iostream>
#include <string>
#include <stack>
using namespace std;int main() {string s;cin >> s;cout << "------s的数据------" << endl;cout << "-----分隔符-----" << endl;cout << s[0]<<endl;cout << "-----分隔符-----" << endl;cout << s[1] << endl;cout << "-----分隔符-----" << endl;cout << "s的长度为:"<<s.length()<<endl;string s1, s2;s1 = "0123456";cout << "------s1的数据------" << endl;cout << "-----分隔符-----" << endl;cout << s1[0] << endl;cout << "-----分隔符-----" << endl;cout << s1[1] << endl;cout << "-----分隔符-----" << endl;cout << "s1的长度为:" << s1.length() << endl;cout << "------s2的数据------" << endl;s2 = 0123456;cout << "-----分隔符-----" << endl;cout << s2[0] << endl;cout << "-----分隔符-----" << endl;cout << s2[1] << endl;cout << "-----分隔符-----" << endl;cout << "s2的长度为:" << s2.length() << endl;return 0;
}

3.不要单独输入s[i]
#include <iostream>
#include <string>
#include <stack>
using namespace std;int main() {string s1;s1[0]=0;s1[1]=1;s1[2]=3;s1[3]='a';for(int i=0;i<s1.length();i++){cout<<s1[i]<<endl;}cout<<"字符串长度="<<s1.length()<<endl; cout<<"--------分割--------"<<endl;string s; s[0]=344;s[1]=33;cout<<s[0]<<endl;cout<<s[1]<<endl;cout<<"字符串s长度="<<s.length()<<endl; return 0;
}
