STL/vector μ capacity μ reserve ν¨μμ μ
κ²°κ³Ό ¶
~cpp vector1μ 100000 λ²μ μ λ ₯ μ ν©λλ€. μ μ₯ κ³΅κ° μμ½μ νμ§ μμ΅λλ€. k: 0, new capacity: 1 k: 1, new capacity: 2 k: 2, new capacity: 4 k: 4, new capacity: 8 k: 8, new capacity: 16 k: 16, new capacity: 32 k: 32, new capacity: 64 k: 64, new capacity: 128 k: 128, new capacity: 256 k: 256, new capacity: 512 k: 512, new capacity: 1024 k: 1024, new capacity: 2048 k: 2048, new capacity: 4096 k: 4096, new capacity: 8192 k: 8192, new capacity: 16384 k: 16384, new capacity: 32768 k: 32768, new capacity: 65536 k: 65536, new capacity: 131072 μ΄μ vector2μ κ°μ μ λ ₯μ ν©λλ€. λ¨, μ μ₯ 곡κ°μ μμ½μ μνν©λλ€.(100000).
μμ€ ¶
~cpp
#include <iostream>
#include <vector>
using namespace std;
/********************************************************/
/* μ΄ νλ‘κ·Έλ¨μ STL Tutorial and Reference Guid 2nd μ */
/* 6.6 μμ μ
λλ€. */
/* νκΈνμ μ£Όμμ 첨λΆνμ΅λλ€. */
/* μ μκΆμ ν΄λΉ μ±
μ λ°λ¦
λλ€. */
/********************************************************/
// μ μ₯ν μλ£ν
class U{
public:
unsigned long id;
U():id(0){}
U(unsigned long x):id(x){}
};
int main()
{
cout << "STL Vecotrμ capacityμ reserveμ λν ν¨μ μνμ 보μ
λλ€."
<< endl;
int N = 100000; // vectorμ μ
λ ₯λ μλ£μ size
vector<U> vector1, vector2;
cout << "vector1μ " << N << " λ²μ μ
λ ₯ μ ν©λλ€. \n"
<< "μ μ₯ κ³΅κ° μμ½μ νμ§ μμ΅λλ€.\n";
int k;
for ( k = 0; k!= N; ++k){
vector<U>::size_type cap = vector1.capacity();
vector1.push_back(U(k));
if( vector1.capacity() != cap )
cout << "k: " << k << ", new capacity: "
<< vector1.capacity() << "\n";
}
vector2.reserve(N);
cout << "\nμ΄μ vector2μ κ°μ μ
λ ₯μ ν©λλ€.\n"
<< "λ¨, μ μ₯ 곡κ°μ μμ½μ μνν©λλ€.(" << N << ").\n";
for ( k = 0; k!= N; ++k){
vector<U>::size_type cap = vector2.capacity();
vector2.push_back(U(k));
// μμ½ λμ΄ μμΌλ―λ‘, μ¬κΈ°μ μ§μ
νμ§ μμ΅λλ€.
if ( vector2.capacity() != cap )
cout << "k: " << k << ", new capacity: "
<< vector2.capacity() << "\n";
}
return 0;
}










