大文件的C ++浮点异常

Question

While executing the following code with a large amount of data (roughly 2MB), I am receiving a Floating Point Exception on line 21.

    #include <bits/stdc++.h>
using namespace std;


int main() {
    std::ios_base::sync_with_stdio(false);
    int S, Q, type, seq, pos;
    int x, y, lastAnswer = 0;
    cin >> S >> Q;
    vector< vector <int> > seqList(S);

    for(int i=0; i<Q; i++){
        cin >> type >> x >> y;
        if( type == 1 ){
            seq = (x^lastAnswer) % S;
            seqList[seq].push_back(y);
            if(seq == 0) lastAnswer = 0;
        }
        else if( type == 2 ){
            seq = (x^lastAnswer) % S;
            pos = (int)(y % seqList[seq].size()); //Line 21
            lastAnswer = seqList[seq][pos];
            cout << lastAnswer << endl;
        }
    }

    return 0;
}

Answer 1

pos = (int)(y % seqList[seq].size()); //Line 21

seqList[seq].size() is 0 . @Lưu Vĩnh Phúc

With a%b , if b == 0 then the behavior is not defined. Many platforms report a floating point exception when an integer division or % by zero is attempted.

Re-write to to detect when seqList[seq].size() == 0 .

Also check S == 0 as it is used with (x^lastAnswer) % S @Jeremy Friesner