PAT甲级——A1050 String Subtraction

Given two strings S​1​​ and S​2​​, S=S​1​​−S​2​​ is defined to be the remaining string after taking all the characters in S​2​​ from S​1​​. Your task is simply to calculate S​1​​−S​2​​ for any given strings. However, it might not be that simple to do it fast.

Input Specification:

Each input file contains one test case. Each case consists of two lines which gives S​1​​ and S​2​​, respectively. The string lengths of both strings are no more than 1. It is guaranteed that all the characters are visible ASCII codes and white space, and a new line character signals the end of a string.

Output Specification:

For each test case, print S​1​​−S​2​​ in one line.

Sample Input:

They are students.
aeiou

Sample Output:

Thy r stdnts.

#include <iostream>
#include <string>
using namespace std;
int main()
{
    int ascll[200] = { 0 };
    string str = "", S1, S2;
    getline(cin, S1);
    getline(cin, S2);//注意S2也可能有空格
    cin >> S2;
    for (int i = 0; i < S2.length(); ++i)
        ascll[S2[i]] = -1;
    for (int i = 0; i < S1.length(); ++i)
        if (ascll[S1[i]] == 0)
            cout << S1[i];
    return 0;
}