調試斷言失敗向量下標越界

Question

當此經過for循環中，我一直有錯誤消息

「調試斷言失敗。矢量下標越界。」

所以我跟蹤的for循環，而當輸入爲

5 
1 100 
2 100 
3 80 
4 60 
5 80 

發生錯誤時我== 2，但我不知道什麼是錯後，我== 2。 請給我一些建議。

錯誤是在這一部分：

for (int i = 0; i < childNum; i++) { 
     if (!IncrementIfFound(value_counts, info.gram_v[i])) { 
      Number_Counts temp(info.gram_v[i]); 
      value_counts.push_back(temp); 
      cout << "Value counts: " << value_counts[i].value << "\t" << value_counts[i].count << endl; 
     } 
    } 

這是我的代碼：

struct Number_Counts 
{ 
    int value; 
    int count; 
    Number_Counts(int _element) { value = _element; count = 1; } 
}; 

struct ChildInfo 
{ 
    vector<int> id_v; 
    vector<int> gram_v; 
}; 

bool IncrementIfFound(vector<Number_Counts> &, int); 

bool IncrementIfFound(vector<Number_Counts> &_Container, int _element) 
{ 
    for (int i = 0; i < _Container.size(); i++) { 
     if (_Container[i].value == _element) { 
      _Container[i].count++; 
      cout << "i : " << i <<" Container value: " << _Container[i].value << " counter: " << _Container[i].count 
       << " size: " << _Container.size() << endl; 
      return true; 
     } 
    } 
    return false; 
} 

int main() { 
    vector<Number_Counts> value_counts; 
    ChildInfo info; 
    int childNum,id, gram = 0; 

    cin >> childNum; 
    for (int i = 0; i < childNum; i++) { 
     cin >> id >> gram; 
     info.id_v.push_back(id); 
     info.gram_v.push_back(gram); 
    } 

    for (int i = 0; i < childNum; i++) { 
     if (!IncrementIfFound(value_counts, info.gram_v[i])) { 
      Number_Counts temp(info.gram_v[i]); 
      value_counts.push_back(temp); 
      cout << "Value counts: " << value_counts[i].value << "\t" << value_counts[i].count << endl; 
     } 
    } 

    return 0; 
} 

Answer 1

for (int i = 0; i < childNum; i++) { 
    if (!IncrementIfFound(value_counts, info.gram_v[i])) { 
     Number_Counts temp(info.gram_v[i]); 
     value_counts.push_back(temp); 
     cout << "Value counts: " << value_counts[i].value << "\t" << value_counts[i].count << endl; 
    } 
} 

試想一下，如果你的if跳過第一n迭代。當訪問value_counts[i].value時，您將訪問數組邊界以外的數據，因爲新值未添加到矢量中。

 auto&& number_count = value_counts.back(); 
     cout << "Value counts: " << number_count.value << "\t" << number_count.count << endl;