[英]std::map with struct as key
i'm try to use a std::map with the key as Struct, but it fails on find the key. 我尝试将std :: map与作为Struct的键一起使用,但是在找到键时失败。 what is wrong here? 这是怎么了 Find does not find but insert will not change the count in the map..... 查找找不到,但插入不会更改地图中的计数。
#pragma once
#include <map>
struct OccTestdef
{
public:
int Typ;
int Length;
OccTestdef(int typ, int length) :Typ(typ), Length(length) {};
bool operator < (const OccTestdef& R) const
{
if (Typ < R.Typ) return true;
if (Length < R.Length) return true;
return false;
}
};
typedef std::map<OccTestdef, int> Testmap;
typedef std::pair<OccTestdef, int> Testpair;
class testocc
{
public:
testocc();
~testocc(){}
bool runtest();
private:
Testmap tests;
int addOrInsert(int left, int num, int value);
};
and the cpp: 和cpp:
#include "testocc.h"
testocc::testocc()
{
tests = Testmap();
}
// Will Return the Map-Value if found or -1 if new Inserted
int testocc::addOrInsert(int left, int num, int value)
{
int res;
OccTestdef tn(left, num);
auto result = tests.find(tn);
if (result != tests.end()) {
res = result->second;
}
else
{
tests.insert(Testpair(tn, value));
res = -1;
}
return res;
}
bool testocc::runtest()
{
int res;
bool result;
// Fill map with 4 Entries
tests.insert(Testpair( OccTestdef(1, 100), 1));
tests.insert(Testpair(OccTestdef(1, 200), 2));
tests.insert(Testpair(OccTestdef(1, 300), 3));
tests.insert(Testpair(OccTestdef(1, 400), 4));
result = (tests.size() == 4);
// Try to find or Insert
res = addOrInsert(1, 200, 2);
//res should be 2
result = (res == 2);
result = (tests.size() == 4);
res = addOrInsert(2, 200, 20);
// Res must be -1 because new inserted
result = (res == -1);
// Count is not changed
result = (tests.size() == 5);
//These fails why?
res = addOrInsert(2, 200, 20);
//res should be 20
result = (res == 20);
return result;
}
I don't understand why the test.find() is not working as expected. 我不明白为什么test.find()不能按预期工作。
Your opeator<
will not order your elements properly because you return true if Typ
is smaller or if Length
is smaller. 您的opeator<
将无法正确排序元素,因为如果Typ
较小或Length
较小,则返回true。
#include <tuple>
bool operator < (const OccTestdef& R) const
{
return std::tie(Typ, Length) < std::tie(R.Typ, R.Length);
}
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