作业1：

#include <iostream>

using namespace std;

namespace myspace {
    string str;
}

int length(string str)
{
    //char *p = &str.at(0);
    const char *p = str.data();
    int count = 0;
    while (*p != 0) {
        p++;
        count++;
    }
    return count;
}
int main()
{
    getline(cin,myspace::str);
    cout << length(myspace::str) << endl;
    return 0;
}

思维导图