C++ code Summary --- 2015.11.8

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C++ code summary

map::iterator it与 map it的区别与联系

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C++

并行程序的执行：

int

coreNum = omp_get_num_procs();

#pragma

omp parallel for

num_threads(coreNum) default(none)

\

private(po_num,

it, queryLabel) \

shared(al_random_select_num,

satisfy_size, satisfy_classifier_label, not_selected, random_index)

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对输入的句子，统计每一个单词出现的次数：

int

main() {

map

size_t>

word_count;

string

word;

while

(cin >>

word) {

++word_count[word];

}

for

(constauto

&w : word_count)

cout

<<

w.first <<"occurs"<<

w.second

<<

((w.second > 1) ? "times"

: "time")

<<

endl;

system("pause");

}

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统计输入中每一个单词出现的次数（排除常见单词，如：”the”,

”a”, ”an”等等）

#include

#include

#include

#include

usingnamespace

std;

int

main() {

map

size_t>

word_count;

set

exclude = {"the",

"a",

"an"};

string

word;

while

(cin >>

word)

if

(exclude.find(word) ==

exclude.end())

++word_count[word];

for

(constauto

&w : word_count)

cout

<<

w.first <<"

occurs "<<

w.second <<"

times "<<

endl;

system("pause");

}

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忽略大小写和标点，如：”example,”

“example.” “Example”应该递增相同计数器。

　　　分为３步骤：

　　　１．先将所有的大写字母改为小写；

　　　２．将所有的标点符号都删去；

　　　３．将转换好的字符串返回．

1 #include

2 #include

3 #include

4 #include

5 #include

6

7 using namespace std;

8

9 string &trans(string &s)

10 {

11 for (int p=0; p

12 if (s[p] >= 'A' && s[p] <= 'Z')

13 s[p] -= ('A'-'a');

14 else if (s[p] == ',' || s[p] == '.')

15 s.erase(p,1);

16 }

17

18 return s;

19 }

20

21 int main(int argc, char *argv[])

22 {

23 ifstream in(argv[1]);

24 if (!in){

25 cout<<"failed to open file !"<

26 exit(1);

27 }

28

29 map word_count;

30 string word;

31 while(in>>word)

32 ++word_count(trans(word));

33

34 for (const auto &w:word_count)

35 cout<<　w.first　<<　" occurs "　<<　w.second　<<　" times "　<

36

37 return 0;

38 }

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对关联容器进行值初始化：

map word_count;

set exclude = {“the”, ”but”, “and”};

map authers = { {“wang”, “xiao”},

{“wang”, ”kui”}, {“wang”, ”jianjun”} };

#include

#include

#include

#include

#include

usingnamespace

std;

int

main() {

vector

ivec;

for

(vector::size_type

i = 0; i != 20; ++i) {

ivec.push_back(i);

ivec.push_back(i);

}

set

iset(ivec.cbegin(), ivec.end());

multiset

miset(ivec.cbegin(), ivec.cend());

cout

<<

ivec.size() <<

endl;

cout

<<

iset.size() <<

endl;

cout

<<

miset.size() <<

endl;

system("pause");

}

pair类型：

一个pair保存两个数据成员，pair是一个用来生成特定类型的模板。

pair anon;

pair word_count;

pair> line;

pair auther {“wangxiao”, “wangkui”};

      pair类型的数据成员是public的，两个成员分别为

first 和

second。

       9. ----

#include #include #include

相关链接