PAT basic 1033

#include <iostream>using namespace std;int main() {    string a, b;    getline(cin, a);//为了防止第一行是空的，不能用cin >> a,用getline(cin, a)    getline(cin, b);    if (a.length() == 0) {        cout << b;        return 0;    }    int flag = 0;    int lena = a.length();    int lenb = b.length();    //检验是否有大写    for (int i = 0; i < lena; i++) {        if (a[i] == '+') {            flag = 1;            a[i] = '#';        }    }    //去除大写字母    if(flag) {        for (int i = 0; i < lenb; i++) {            if (b[i] >= 'A' && b[i] <= 'Z') {                b[i] = '#';            }        }    }    //去除其它字母    for (int i = 0; i < lenb; i++) {        for (int j = 0; j < lena; j++) {            if (a[j] == b[i]) {                b[i] = '#';            }            if (a[j] >= 'A' && a[j] <= 'Z' && b[i] == a[j] + 32) {                b[i] = '#';            }        }    }    int flag1 = 0;    //print    for (int i = 0; i < lenb; i++) {        if (b[i] != '#') {            cout << b[i];            flag1 = 1;        }    }    if (flag1 == 0)        cout << endl;    return 0;}