在main()内一行中初始化/设置char * argv [] [英] Initialize/set char *argv[] inside main() in one line
问题描述
我想在main()内部初始化/设置char *argv[]，以便以后可以在程序中使用argv[1], argv[2]....
I want to initialize/set char *argv[] inside the main() so that I can use argv[1], argv[2]... later in my program.
到目前为止，我知道如何通过两种方式做到这一点:
Up to now, I know how to do this in two ways:
-
对于
int main()，使用一行作为:
int main()
{
char *argv[] = {"programName", "para1", "para2", "para3", NULL};
}
请注意，最后使用NULL是因为argv数组中的指针指向根据定义NULL终止的C字符串.
Note that, using NULL in the end is because the pointers in the argv array point to C strings, which are by definition NULL terminated.
对于int main(int argc, char* argv[])，我必须使用多行作为:
For int main(int argc, char* argv[]), I have to use multiple lines as:
int main(int argc,char* argv[])
{
argv[0] = "programName";
argv[1] = "para1";
argv[2] = "para2";
argv[3] = "para3";
}
我的问题是如何将这两种方法结合在一起，即仅使用一行为int main(int argc, char* argv[])初始化它?特别是，我希望能够做到这一点(目前这是错误的):
My question is that how can I combine these two methods together, i.e. use only one line to initialize it for int main(int argc, char* argv[])? Particularly, I want to be able to do like this (this will be wrong currently):
int main(int argc, char* argv[])
{
argv = {"programName", "para1", "para2", "para3", NULL};
}
我该怎么做?
编辑:我知道可以在Debugging Command Arguments中设置argv[].我要在main()中进行编辑的原因是，我不想每次都为新的测试用例(不同的argv[]设置)使用Debugging Command Arguments.
Edit: I know argv[] can be set in Debugging Command Arguments. The reason that I want to edit them in main() is that I don't want to bother to use Debugging Command Arguments every time for a new test case (different argv[] setting).
推荐答案
最安全的方法可能是不写到argv引用的内存中(可能不像您想象的那样结构化)，而是有另一个大容量:
The safest way is probably don't write into argv referred memory, (that may not be structured as you think), but having another bulk:
int main(int argc, const char** argv)
{
const char* n_argv[] = { "param0", "param1", "param2" };
argv = n_argv;
...
}
这会将argv从其原始内存(由调用方拥有，并保留在其中)转移到另一个内存中，该内存将在main()的生命期内存在.
This will distract argv from it original memory (owned by the caller, that remains there) to another that will exist for the life of main().
请注意，必须使用const char*来避免使用已弃用的"*分配给char **的字符串"消息.
Note that const char* is required to avoid the deprecated "*string assigned to char**" message.
注意:该代码已在Linux上使用GCC 4.8.1进行了编译，结果如下:
NOTE: this code had been compiled with GCC 4.8.1 on Linux giving the following results:
make all
Building file: ../main.cpp
Invoking: GCC C++ Compiler
g++ -O0 -g3 -pedantic -Wall -c -std=c++11 -o "main.o" "../main.cpp"
Finished building: ../main.cpp
Building target: e0
Invoking: GCC C++ Linker
g++ -o "e0" ./main.o
Finished building target: e0
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