C++ STL vector, resize() and size() 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++ size() to return the number of elements in the vector and resize() to specify a new size for a vector in C++ programming

To show: Using the C++ size() to return the number of elements in the vector and resize() to specify a new size for a vector in C++ programming

 

// C++ STL vector, resize() and size()

#include <vector>

#include <iostream>

using namespace std;

 

int main(void)

{

unsigned int i;

// vector container

vector <int> vec1;

 

// push data into the container

vec1.push_back(40);

vec1.push_back(20);

vec1.push_back(10);

vec1.push_back(12);

 

// print the data

cout<<"vec1 vector data: ";

for(i=0; i<vec1.size(); ++i)

cout<<vec1[i]<<' ';

cout<<endl;

 

// resize to 5 and add data at the end

cout<<"\nOperation: vec1.resize(5,30);"<<endl;

vec1.resize(5,30);

cout<<"The size of vec1 vector is "<<vec1.size()<<endl;

cout<<"The value of the last object is "<<vec1.back()<<endl;

cout<<"\nNew vec1 vector data: ";

for(i=0; i<vec1.size(); ++i)

cout<<vec1[i]<<' ';

cout<<endl;

cout<<"\nOperation: vec1.resize(4);"<<endl;

vec1.resize(4);

cout<<"\nNew vec1 vector data: ";

for(i=0; i<vec1.size(); ++i)

cout<<vec1[i]<<' ';

cout<<endl;

cout<<"\nThe new size of vec1 vector is "<<vec1.size()<<endl;

cout<<"The value of the last object is "<<vec1.back()<<endl;

return 0;

}

 

Output examples:

 

vec1 vector data: 40 20 10 12

Operation: vec1.resize(5,30);

The size of vec1 vector is 5

The value of the last object is 30

New vec1 vector data: 40 20 10 12 30

Operation: vec1.resize(4);

New vec1 vector data: 40 20 10 12

The new size of vec1 vector is 4

The value of the last object is 12

Press any key to continue . . .

 

 

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