STL和泛型编程笔记之容器的分类和测试笔记
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STL和泛型编程笔记之容器的分类和测试笔记
一、STL六大部件
- Containers
- Allocators
- Algorithms
- Adapters
- Iterators
- Functors
使用各个容器的测试
#include <iostream>
#include <algorithm>
#include <functional>
using namespace std;
int main(int argc, char const *argv[])
int ai[6] = 12,45,6,78,125,69;
vector<int,allocator<int>> v(ai,ai+6);
//count_if: Return number of elements in range satisfying condition
cout << count_if(v.begin(),v.end(),not1(bind2nd(less<int>,40)));
return 0;
二、容器的分类与结构
三、容器的测试
测试程序的辅助函数
using std::cin;
using std::cout;
using std::string;
//获取目标数值
long get_a_target_long()
long target = 0;
cout<< "target (0~ "<< RAND_MAX << "): ";
cin >> target;
return target;
//获取目标字符串
string get_a_target_string()
long target=0;
char buf[10];
cout<< "target(0~"<<RAND_MAX<<"): ";
cin>>target;
snprintf(buf,10,"%d",target);
return string(buf);
//比较long
int compareLongs(const void* a,const void* b)
return *(long*)a - *(long*)b;
int compareStrings(const void* a,const void* b)
if(*(string*)a>*(string*)b)
return 1;
else if(*(string*)a>*(string*)b)
return -1;
else
return 0;
1.Sequence Container
array
namespace testArray
const long A_SIZE = 500000L;
void test_array()
cout<< "\\ntest_array()-----------\\n";
array<long,A_SIZE> c;
//count time
long t_start = clock();
//初始化元素
for (int i = 0; i < A_SIZE; ++i)
c[i] = rand();
//output
cout << "count time :" << (clock() - t_start) << endl;//初始化整个数组的时间
cout << "c.size() :" << c.size() << endl;//数组大小
cout << "c.front() :" << c.front() << endl;//首元素值
cout << "c.back() :" << c.back() << endl;//尾元素值
cout << "c.data() :" << c.data() << endl;//首地址
//find target
long target = get_a_target_long();
t_start = clock();
//先排序后二分查找目标元素
qsort(c.data(),A_SIZE,sizeof(long),compareLongs);
long* pItem = (long*)bsearch(&target,c.data(),A_SIZE,sizeof(long),compareLongs);
//输出查找的时间
cout<<"qsort()+ bsearch() count time: " << (clock()-t_start)<<endl;
//输出查找结果
if(pItem!=NULL)
cout << "found: " << *pItem <<endl;
else
cout << "not found" <<endl;
int main()
testArray::test_array();
return 0;
终端输出结果如下:
vector
成倍地申请内存空间,当申请不到的时候终止程序
#include <vector>
#include <string>
#include <cstdlib>//bsearch
#include <cstdio>//snprintf
#include <iostream>
#include <stdexcept>//try...catch()...
#include <ctime>//clock()
#include <algorithm>//find,sort
namespace testVector
void test_vector(long& value)
cout<< "test_vector()-----------------"<<endl;
vector<string> c;
long t = clock();
char buf[10];
for (long i = 0; i < value; i++)
try
snprintf(buf,10,"%d",rand());//初始化每一个元素
c.push_back(string(buf));//vector容器的结果是只能将添加的元素加到末尾,即函数push_back()
catch(exception& p)
cout <<"i="<< p.what() << endl;
abort();//终止程序
//输出
cout <<"count time: " << (clock()-t)<<endl;
cout << "c.size()" << c.size() << endl;//返回c中的元素数
cout << "c.front()" << c.front() << endl;
cout << "c.data()" << c.data() << endl;
cout << "c.capacity()" << c.capacity() << endl;//返回当前为vector分配的存储空间的大小,以元素表示。
string target = get_a_target_string();
//两种查找方式花费时间比较
t = clock();
//使用全局find函数函数直接查找
auto pItem =::find(c.begin(),c.end(),target);
//输出查找的时间
cout<<"find() count time: " << (clock()-t)<<endl;
//输出查找结果
if(pItem!=c.end()) //如果没有等于末尾元素地址则说明找到这个元素
cout << "found: " << *pItem <<endl;
else
cout << "not found" <<endl;
t = clock();
//使用sort函数函数先排序后查找
sort(c.begin(),c.end());
string* pItem =(string*)bsearch(&target,c.data(),c.size(),sizeof(string),compareStrings);
//输出查找的时间
cout<<"sort()+ bsearch() count time: " << (clock()-t)<<endl;
//输出查找结果
if(pItem!=NULL) //如果没有等于末尾元素地址则说明找到这个元素
cout << "found target: " << *pItem <<endl;
else
cout << "not found" <<endl;
// namespace testVector
int main()
long v = 1000000L;
testVector::test_vector(v);
return 0;
输出结果
由此观之,使用find直接查找元素比先排序后查找快速
list
#include <iostream>
#include <ctime>//clock
#include <list>
#include <cstdio>//snprintf
#include <stdexcept>//try..catch..
#include <algorithm>//find,sort
namespace testList
void test_list(long& v)
cout<< "test_list()-----------------"<<endl;
list<string> c;
long t = clock();
char buf[10];
for (long i = 0; i < v; i++)
try
snprintf(buf,10,"%d",rand());//初始化每一个元素
c.push_back(string(buf));
catch(exception& p)
cout <<"i="<< p.what() << endl;
abort();//终止程序
//输出
cout <<"count time: " << (clock()-t)<<endl;
cout << "c.size():" << c.size() << endl;//返回列表容器中的元素个数
cout << "c.max_size():" << c.max_size() << endl;//返回列表容器所能容纳的最大元素数。
cout << "c.back():" << c.back() << endl;
cout << "c.front():" << c.front() << endl;
string target = get_a_target_string();
//两种查找方式花费时间比较
t = clock();
//使用全局find函数函数直接查找
auto pItem =::find(c.begin(),c.end(),target);
//输出查找的时间
cout<<"find() count time: " << (clock()-t)<< " ms"<<endl;
//输出查找结果
if(pItem!=c.end()) //如果没有等于末尾元素地址则说明找到这个元素
cout << "found: " << *pItem <<endl;
else
cout << "not found" <<endl;
t = clock();
//使用容器自带的sort函数排序后
c.sort();
//输出查找的时间
cout<<"c.sort() count time: " << (clock()-t)<< " ms"<<endl;
// namespace testList
int main()
long v = 1000000L;
testList::test_list(v);
return 0;
测试结果:
find函数的查找比排序快
Forward_list
#include <iostream>
#include <stdexcept>//try...catch
#include <algorithm>//find,sort
#include <cstdio>//snprintf
#include <cstdlib>//bsearch, abort()
#include <ctime>//clock
#include <forward_list>
namespace testForwardList
void test_forwardlist(long& v)
cout<< "test_list()-----------------"<<endl;
forward_list<string> c;
long t = clock();
char buf[10];
for (long i = 0; i < v; i++)
try
snprintf(buf,10,"%d",rand());//初始化每一个元素
c.push_front(string(buf));
catch(exception& p)
cout <<"i="<< p.what() << endl;
abort();//终止程序
//输出
cout <<"count time: " << (clock()-t)<<endl;
cout << "c.max_size():" << c.max_size() << endl;//返回列表容器所能容纳的最大元素个数。
cout << "c.front():" << c.front() << endl;
//单向链表无size()函数和back()函数
string target = get_a_target_string();
//两种查找方式花费时间比较
t = clock();
//使用全局find函数函数直接查找
auto pItem =::find(c.begin(),c.end(),target);
//输出查找的时间
cout<<"find() count time: " << (clock()-t)<< " ms"<<endl;
//输出查找结果
if(pItem!=c.end()) //如果没有等于末尾元素地址则说明找到这个元素
cout << "found: " << *pItem <<endl;
else
cout << "not found" <<endl;
t = clock();
//使用容器自带的sort函数排序后
c.sort();
//输出查找的时间
cout<<"c.sort() count time: " << (clock()-t)<< " ms"<<endl;
// namespace testForwardList
int main()
long v = 1000000L;
testForwardList::test_forwardlist(v);
return 0;
测试结果:
find()函数查找比排序快
slist
#include <iostream>
#include <cstdio>//snprintf
#include <cstdlib>//abort
#include <stdexcept>//try...catch
#include <ctime>
#include <ext\\slist>
#include <string>
namespace testSList
void test_slist(long& v)
cout<<"test_slist()------------------"<<endl;
__gnu_cxx::slist<string> c;
char buf[10];
long t = clock();
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