c++ unique函数返回值

转自：https://blog.csdn.net/aggressive_snail/article/details/51332659

std::unique

功能：对有序的容器重新排列，将第一次出现的元素从前往后排，其他重复出现的元素依次排在后面

返回值：返回迭代器，迭代器指向的是重复元素的首地址

看不懂表达的看看下面这个简图：

有序的容器：

1

1

2

3

3

4

4

4

5

6

unique处理过的容器：

unique

unique

unique

unique

unique

unique

迭代器指向的地址

1

2

3

4

5

6

1

3

4

4

（上表迭代器是指向倒数第四个数1）

#include<iostream>
#include<string>
#include <algorithm>
#include <vector>
 
using namespace std;
typedef vector <string> VECTOR_STRING;
 
void printVec(VECTOR_STRING& vec)
{
    for(size_t nItem = 0; nItem < vec.size(); nItem++)
    {
        cout << "Name[" << nItem << "] = \" ";
        cout << vec[nItem] << " \" " << endl;
    }
    cout << endl;
}
int main()
{
    VECTOR_STRING vecNames;
    vecNames.push_back("john");
    vecNames.push_back("bob");
    vecNames.push_back("john");
    vecNames.push_back("vctor");
    vecNames.push_back("vctor");
    vecNames.push_back("jim");
    vecNames.push_back("bob");
    vecNames.push_back("jim");
    cout << "the initial contents are:" << endl;
    printVec(vecNames);
    sort(vecNames.begin(), vecNames.end());
    cout << "after sort(), contents are:" << endl;
    printVec(vecNames);
    VECTOR_STRING::iterator iNameTor;
    iNameTor = unique(vecNames.begin(), vecNames.end());
    cout << "after unique(), contents are:" << endl;
    printVec(vecNames);
    cout << "unique return a iterator, point to the first Duplicate element " << endl;
    cout << iNameTor - vecNames.begin() << endl << endl;
    vecNames.erase(iNameTor, vecNames.end()); //删除重复元素
    cout << "after erase(), contents are:" << endl;
    printVec(vecNames);
}