[英]Iterating over a vector of structs and dereferencing the iterator
我正在遍历struct
的vector
,然后尝试取消引用迭代器。 我认为我缺少一些逻辑并做错了,或者只是语法不正确。
代码如下,并包含许多调试输出:
#include <fstream>
#include <map>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
ifstream fin("gift1.in", ios::in);
ofstream fout("gift1.out", ios::out);
unsigned short NP;
struct person
{
string name;
unsigned int gave;
unsigned int received;
};
vector<person> accounts;
string tmp_name;
fin >> NP;
accounts.resize(NP);
for (auto& i : accounts)
{
fin >> tmp_name;
//fout << "Just read this name: " << tmp_name << "\n";
i.name = tmp_name;
i.gave = 0;
i.received = 0;
}
fout << "\n";
for (unsigned int j = 1; j <= NP; j++)
{
string giver_name;
fin >> giver_name;
fout << "Read a name #" << j << ": " << giver_name << "\n";
auto vpit = find_if(accounts.begin(), accounts.end(), [&giver_name](const person& pers) -> bool {return pers.name != giver_name; });
if (vpit == accounts.end())
{
fout << "Couldn't find this giver in accounts\n";
}
else
{
person& found = *vpit; // the logic is probably wrong here
fout << "\nDebug info: \n\t Giver#" << j << "; \n\t iterator->name ==" << vpit->name << "; \n\t iterator->gave == " << vpit->gave << "; \n\t iterator->received == " << vpit ->received << "\n";
fout << "Found " << found.name << " in accounts; proceeding\n";
//further code
}
我可能做错了什么?
如果要查找具有给定值的向量元素,则必须使用相等运算符
auto vpit = find_if( accounts.begin(), accounts.end(),
[&giver_name] (const person& pers) { return pers.name == giver_name; } );
至于我,第二个循环
for (unsigned int j = 1; j <= NP; j++)
{
string giver_name;
fin >> giver_name;
//...
看起来可疑。
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