c++测试程序运行时间遇到的有关问题

c++测试程序运行时间遇到的问题

C/C++ code

#include <iostream>
#include <string.h>
#include <stdio.h>
#include <time.h>
using namespace std;

clock_t start1,start2,end1,end2;
//C-style character string implementation
start1 = clock();
const char *pc = "a very long literal string";
const size_t len = strlen(pc);

for (size_t ix = 0; ix != 1000000; ++ix) {
        char *pc = new char[len + 1];
        strcpy(pc2, pc);
        if (strcmp(pc2, pc))
                ;
        delete [] pc2;
}
end1 = clock();

cout << "C-style character need "<< end1-start1 << endl;

//string implementation
start2 = clock();
string str("a very long literal string");

for (int ix = 0; ix != 1000000; ++ix) {
        string str2 = str;
        if (str != str2)
                ;
}
end2 = clock();

cout << "C-style character need "<< end1-start1 << endl;

报错如下：
[wsl@localhost timecmp]$ g++ -o a timecmp.cpp 
timecmp.cpp:9: error: expected constructor, destructor, or type conversion before ‘=’ token
timecmp.cpp:13: error: expected unqualified-id before ‘for’
timecmp.cpp:13: error: expected constructor, destructor, or type conversion before ‘!=’ token
timecmp.cpp:13: error: expected unqualified-id before ‘++’ token
timecmp.cpp:20: error: expected constructor, destructor, or type conversion before ‘=’ token
timecmp.cpp:22: error: expected constructor, destructor, or type conversion before ‘<<’ token
timecmp.cpp:25: error: expected constructor, destructor, or type conversion before ‘=’ token
timecmp.cpp:28: error: expected unqualified-id before ‘for’
timecmp.cpp:28: error: expected constructor, destructor, or type conversion before ‘!=’ token
timecmp.cpp:28: error: expected unqualified-id before ‘++’ token
timecmp.cpp:33: error: expected constructor, destructor, or type conversion before ‘=’ token
timecmp.cpp:35: error: expected constructor, destructor, or type conversion before ‘<<’ token


------解决方案--------------------
LZ ，你main函数都没有啊。
------解决方案--------------------

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LZ ，你main函数都没有啊。