为什么这个C++程序不能编译？

Question

这是我正在编译的程序。

#include <iostream> 
#include <string> 
#include <vector> 
#include <unistd.h> 
using namespace std; 

vector<string> paramlist; 
const char *programname = "abc"; 

const char **args = new const char* [paramlist.size()+2]; // extra room for program name and sentinel 
args [0] = programname;   // by convention, args[0] is program name 
for (int j = 0; j < paramlist.size()+1; ++j)  // copy args 
args [j+1] = paramlist[j] .c_str(); 

args [paramlist.size()+1] = NULL; // end of arguments sentinel is NULL 

execv (programname, (char **)args); 

当我尝试编译我收到以下错误消息：

test.cpp:11: error: expected constructor, destructor, or type conversion before ‘=’ token 
test.cpp:12: error: expected unqualified-id before ‘for’ 
test.cpp:12: error: expected constructor, destructor, or type conversion before ‘<’ token 
test.cpp:12: error: expected unqualified-id before ‘++’ token 
test.cpp:15: error: array bound is not an integer constant 
test.cpp:15: error: expected constructor, destructor, or type conversion before ‘=’ token 
test.cpp:17: error: expected constructor, destructor, or type conversion before ‘(’ token 

Answer 1

您至少需要一个int main function。

Answer 2

你的程序包含代码，但它需要包含在一个函数中。尝试使用int main之类的函数将using namespace std;行后的所有代码包装起来。 Google为任何“Hello world”C++示例查看示例。