C++ STL set, count() code example

 

Compiler: Visual C++ Express Edition 2005

Compiled on Platform: Windows XP Pro SP2

Header file: Standard

Additional library: none/default

Additional project setting: Set project to be compiled as C++

Project -> your_project_name Properties -> Configuration Properties -> C/C++ -> Advanced -> Compiled As: Compiled as C++ Code (/TP)

Other info: none

To do: Using the C++ count() to return the number of elements in a set whose key matches a parameter-specified key in C++ programming

To show: How to use the C++ STL set, count() to return the number of elements in a set whose key matches a parameter-specified key in C++ programming

 

// set, count()

#include <set>

#include <iostream>

using namespace std;

 

int main(void)

{

// set container

set <int> st1;

size_t i;

 

// insert data

st1.insert(1);

st1.insert(2);

st1.insert(1);

 

// keys must be unique in set, duplicates are ignored

i = st1.count(1);

cout<<"The number of elements in st1 set with a sort key of 1 is: "<<i<<endl;

i = st1.count(2);

cout<<"The number of elements in st1 set with a sort key of 2 is: "<<i<<endl;

i = st1.count(3);

cout<<"The number of elements in st1 set with a sort key of 3 is: "<<i<<endl;

return 0;

}

 

Output examples:

 

The number of elements in st1 set with a sort key of 1 is: 1

The number of elements in st1 set with a sort key of 2 is: 1

The number of elements in st1 set with a sort key of 3 is: 0

Press any key to continue . . .

 

 

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