不允许重复的函数?(C++)
A function where duplicates are not allowed? (C++)
所以我假设修改一个函数,它的初始目的是使字符串的数组中不能有超过6个项。这是代码
template<class ItemType>
bool Bag<ItemType>::Add(const ItemType& new_entry)
{
bool has_room_to_add = item_count_ < max_items_;
if (has_room_to_add)
{
items_[item_count_] = new_entry;
item_count_++;
} // end if
return has_room_to_add;
} // end add
这是我的尝试。
template<class ItemType>
bool set<ItemType>::Add(const ItemType& new_entry)
{
string checker[] = { "Joker", "Ace", "Two", "Three",
"Four", "Five", "Six", "Seven",
"Eight", "Nine", "Ten", "Jack",
"Queen", "King" };
bool has_room_to_add = item_count_ < max_items_;
//compares the new entry to every item in the string and if there is a duplicate, the loop breaks and nothing is added.
if (has_room_to_add)
{
for ( int i =0; i <=13; i++)
{
if (checker[i] == items_[item_count_])
break; //ends loop
else if (i==13)
{
items_[item_count_] = new_entry;
break; //ends loop
} // end if
} // end for
} //end if
// increases item_count_ if a new item is added to a set.
if (items_[item_count_] == new_entry)
item_count_++;
return has_room_to_add;
} // end add
但这不仅不能防止重复,还打破了不允许超过6个项目的初衷,如果有更多项目,就会失控。有人能告诉我我做错了什么吗?
实现这一点的C++方法是使用std::set
,因为std::set
不存储重复项。
#include <set>
#include <string>
#include <iostream>
#include <iterator>
#include <algorithm>
using namespace std;
int main()
{
string checker[] = { "Joker", "Ace", "Two", "Three",
"Four", "Five", "Six", "Seven",
"Eight", "Nine", "Ten", "Jack",
"Queen", "King", "Joker", "Ace", "Two", "Three",
"Four", "Five", "Six", "Seven",
"Eight", "Nine", "Ten", "Jack",
"Queen", "King" };
set<string> mySet;
// insert all of the items in the array into the set
copy(checker, checker + sizeof(checker)/sizeof(checker[0]), std::inserter(mySet, mySet.begin()));
// output the results
copy(mySet.begin(), mySet.end(), std::ostream_iterator<string>(cout, "n"));
}
输出:
Ace
Eight
Five
Four
Jack
Joker
King
Nine
Queen
Seven
Six
请注意,即使试图在集合中放置重复的条目,也只存在一个条目。将项目数量限制为6:
#include <set>
#include <string>
#include <iostream>
#include <iterator>
#include <algorithm>
using namespace std;
int main()
{
string checker[] = { "Joker", "Ace", "Two", "Three",
"Four", "Five", "Six", "Seven",
"Eight", "Nine", "Ten", "Jack",
"Queen", "King", "Joker", "Ace", "Two", "Three",
"Four", "Five", "Six", "Seven",
"Eight", "Nine", "Ten", "Jack",
"Queen", "King" };
set<string> mySet;
// insert all of the items in the array into the set
for (size_t i = 0; i < sizeof(checker)/sizeof(checker[0]); ++i)
{
if ( mySet.size() < 6 )
mySet.insert(checker[i]);
else
break;
}
// output the results
copy(mySet.begin(), mySet.end(), std::ostream_iterator<string>(cout, "n"));
}
输出:
Ace
Five
Four
Joker
Three
Two
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