결과

strA==strA

==> elapsed time : 1.08 sec

strA==strB

==> elapsed time : 1.09 sec

strcmp(szA,szB)

==> elapsed time : 0.12 sec

strcmp(szA,szA)

==> elapsed time : 0.11 sec

strcmp(strA,strB)

==> elapsed time : 0.25 sec

strcmp(strA,strA)

==> elapsed time : 0.25 sec

Source Code

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <string>

#include “Blib.h”
using namespace std;

#define TEST_SIZE 1<<20

#define ITER 1<<25
void compare()

{

  string strBuffer1(TEST_SIZE, ‘a’);

  string strBuffer2(TEST_SIZE, ‘b’);
  char szBuffer1[TEST_SIZE+1];

  memset(szBuffer1 , ‘a’, TEST_SIZE);

  szBuffer1[TEST_SIZE]=’\0′;

  char szBuffer2[TEST_SIZE+1];

  memset(szBuffer2 , ‘b’, TEST_SIZE);

  szBuffer2[TEST_SIZE]=’\0′;
  Blib::TStopWatch w;

  puts(“strA==strA\n”);

  for (int i=0;i<ITER;i++)

    strBuffer1 == strBuffer2;

  w.Print(stderr);
  w.Reset();

  puts(“strA==strB\n”);

  for (int i=0;i<ITER;i++)

    strBuffer1 == strBuffer2;

  w.Print(stderr);
  w.Reset();

  puts(“strcmp(szA,szB)\n”);

  for (int i=0;i<ITER;i++)

    strcmp(szBuffer1, szBuffer2);

  w.Print(stderr);
  w.Reset();

  puts(“strcmp(szA,szA)\n”);

  for (int i=0;i<ITER;i++)

    strcmp(szBuffer1, szBuffer1);

  w.Print(stderr);
  w.Reset();

  puts(“strcmp(strA,strB)\n”);

  for (int i=0;i<ITER;i++)

    strcmp(strBuffer1.c_str(), strBuffer2.c_str());

  w.Print(stderr);
  w.Reset();

  puts(“strcmp(strA,strA)\n”);

  for (int i=0;i<ITER;i++)

    strcmp(strBuffer1.c_str(), strBuffer1.c_str());

  w.Print(stderr);

}
main()

{

  compare();

}

분석

어이없다;;; string 안에 뭐가 들어있길래 저리 차이가 나누???