In [ ]:

#include <iostream>
#include <stack>
#include <queue>
#include <iterator>
#include <sstream>
#include <string>

using namespace std;

Stack¶

In [29]:

stack<int> st;

// push three elements into the stack
st.push(1);
st.push(2);
st.push(3);

In [30]:

st

Out[30]:

@0x7f2275130488

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// pop and print two elements from the stack
cout << st.top() << ' ';
st.pop();
cout << st.top() << ' ';
st.pop();

3 2

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// modify top element
st.top() = 77;

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// push two new elements
st.push(4);
st.push(5);

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// pop one element without processing it
st.pop();

In [35]:

// pop and print remaining elements
while (!st.empty()) {
    cout << st.top() << ' ';
    st.pop();
}
cout << endl;

4 77

Queue¶

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queue<string> q;

// insert three elements into the queue
q.push("Bob");
q.push("Sue");
q.push("Tim");

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// read and print two elements from the queue
cout << q.front() << " ";
q.pop();
cout << q.front() << " ";
q.pop();

Bob Sue

In [38]:

// insert two new elements
q.push("Jasper");
q.push("Homer");

// skip one element
q.pop(); // alien abduction

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// read and print two elements
cout << q.front() << " ";
q.pop();
cout << q.front() << endl;
q.pop();

Jasper Homer

In [40]:

q.push("Zoey");

// print number of elements in the queue
cout << "Number of people waiting in line: " << q.size() << endl;

Number of people waiting in line: 1

Reverse Iterators¶

In [41]:

vector<int> v{1,2,3,4};
vector<int> w(4);

copy(v.rbegin(), v.rend(), w.begin());
w

Out[41]:

{ 4, 3, 2, 1 }

In [42]:

for (auto it = v.rbegin(); it != v.rend(); ++it) {
    cout << *it << " ";
}
cout << endl;

4 3 2 1

Insert Iterators¶

In [47]:

vector <int> v, w;
for(int i = 3; i <= 5; i++) { 
    v.push_back(i); 
    w.push_back(i * 10); 
}
v

Out[47]:

{ 3, 4, 5 }

In [44]:

Out[44]:

{ 30, 40, 50 }

In [45]:

v.size()

Out[45]:

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copy(w.begin(), w.end(), v.begin());
v

Out[46]:

{ 30, 40, 50 }

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copy(w.begin(), w.end(), back_inserter(v));
v

Out[48]:

{ 3, 4, 5, 30, 40, 50 }

In [49]:

deque <int> v, w;
for(int i = 3; i <= 5; i++) { 
    v.push_back(i); 
    w.push_back(i * 10);
}
v

Out[49]:

{ 3, 4, 5 }

In [50]:

copy(w.begin(), w.end(), front_inserter(v));
v

Out[50]:

{ 50, 40, 30, 3, 4, 5 }

In [51]:

vector <int> v, w;
for(int i = 3; i <= 5; i++) { 
    v.push_back(i); 
    w.push_back(i * 10);
}
v

Out[51]:

{ 3, 4, 5 }

In [52]:

copy(w.begin(), w.end(), inserter(v, v.begin() + 1));
v

Out[52]:

{ 3, 30, 40, 50, 4, 5 }

Stream Iterators¶

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vector <int> v; 
copy(istream_iterator <int>(cin),
     istream_iterator <int>(), // works like end
     back_inserter(v));
v

Out[53]:

{ 12, 34, 56, 455, 7892, 234789, 78934 }

In [54]:

vector <int> v{0,1,2,3,4};
ostream_iterator <int> outIter(cout, " ");
copy(v.begin(), v.end(), outIter);

0 1 2 3 4

StringStream¶

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std::string paragraph = R"""(
    It was the best of times
    it was the worst of times
    it was the age of wisdom
    it was the age of foolishness
    it was the epoch of belief
    it was the epoch of incredulity
    it was the season of Light
    it was the season of Darkness
    it was the spring of hope
    it was the winter of despair
    we had everything before us
    we had nothing before us
    we were all going direct to Heaven
    we were all going direct the other way
    in short
    the period was so far like the present period
    that some of its noisiest authorities insisted on its being received
    for good or for evil
    in the superlative degree of comparison only
)""";

In [56]:

std::stringstream stream(paragraph);

// count the number of times each word occurs in the input
std::map<string, size_t> word_count;  // empty map from string to size_t
std::string              word;

while (stream >> word) {
    ++word_count[word];
}

for (const auto &w : word_count)
    cout << w.first << " occurs " << w.second << " times" << endl;

Darkness occurs 1 times
Heaven occurs 1 times
It occurs 1 times
Light occurs 1 times
age occurs 2 times
all occurs 2 times
authorities occurs 1 times
before occurs 2 times
being occurs 1 times
belief occurs 1 times
best occurs 1 times
comparison occurs 1 times
degree occurs 1 times
despair occurs 1 times
direct occurs 2 times
epoch occurs 2 times
everything occurs 1 times
evil occurs 1 times
far occurs 1 times
foolishness occurs 1 times
for occurs 2 times
going occurs 2 times
good occurs 1 times
had occurs 2 times
hope occurs 1 times
in occurs 2 times
incredulity occurs 1 times
insisted occurs 1 times
it occurs 9 times
its occurs 2 times
like occurs 1 times
noisiest occurs 1 times
nothing occurs 1 times
of occurs 12 times
on occurs 1 times
only occurs 1 times
or occurs 1 times
other occurs 1 times
period occurs 2 times
present occurs 1 times
received occurs 1 times
season occurs 2 times
short occurs 1 times
so occurs 1 times
some occurs 1 times
spring occurs 1 times
superlative occurs 1 times
that occurs 1 times
the occurs 14 times
times occurs 2 times
to occurs 1 times
us occurs 2 times
was occurs 11 times
way occurs 1 times
we occurs 4 times
were occurs 2 times
winter occurs 1 times
wisdom occurs 1 times
worst occurs 1 times

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