字符串分隔//不知道为什么我写的string溢出错误

#include
#include
#include<string>
using namespace std;
string str;
#define N 8
int j = 0;
/*
int main() {
    while (getline(cin, str)) {
        while (str.size() > 8) {
            cout << str.substr(0, 8) << endl;
            str = str.substr(8, str.size() - 8);
        }
        int len = str.length();
        if (len == 8) {
            cout << str << endl;
        }
        else {
            for (int i = len; i < 8; i++) {
                str += '0';
            }
            cout << str << endl;
        }
    }
    return 0;    
}
    */

int main() {
    while (getline(cin, str)) {
        for (int i = str.length()%8; i < 8; ++i) {
            str += '0';
        //    cout << str.size() <
        }
        cout << str << endl;
        int t = str.length()/8;
        //cout << t << endl;
        for (int i = 0; i < t+1; i++) {
            for (int j = 0; j <8; ++j) {
                double a = 8 * i;
                cout << str[ a + j];
            }
            cout << endl;
        }
    }

}