C：如何将函数存储到变量中？

基本上,我想存储指向一个变量中的函数的指针,所以我可以从命令行指定要使用的函数.

所有函数返回并获取相同的值.

unsigned int func_1 (unsigned int var1)
unsigned int func_2 (unsigned int var1)

function_pointer = either of the above?

所以我可以通过去：function_pointer(my_variable)来调用它？

编辑：
根据@ larsmans的建议,我已经得到了：
config.h中：

class Config
{
public:
    unsigned static int (*current_hash_function)(unsigned int);
};

Config.cpp：

#include "Config.h"
#include "hashes.h"
unsigned static int (*current_hash_function)(unsigned int) = kennys_hash_16;

hashes.h：

unsigned int kennys_hash(unsigned int out);
unsigned int kennys_hash_16(unsigned int out);

hashes.cpp：

just implements the functions in the header

main.cpp中：

#include "Config.h"
#include "hashes.h"
// in test_network:
    unsigned int hashed = Config::current_hash_function(output_binary);

//in main():
        else if (strcmp(argv[i],"-kennys_hash_16") == 0)
        {
            Config::current_hash_function = kennys_hash_16;
        }
        else if (strcmp(argv[i],"-kennys_hash_8") == 0)
        {
            Config::current_hash_function = kennys_hash;
        }

我得到的错误：

g++ -o hPif src/main.o src/fann_utils.o src/hashes.o src/Config.o -lfann -L/usr/local/lib 
Undefined symbols:
  "Config::current_hash_function",referenced from:
      test_network()     in main.o // the place in the code I've selected to show
      auto_test_network_with_random_data(unsigned int,unsigned int,unsigned int)in main.o
      generate_data(unsigned int,unsigned int)in main.o
      _main in main.o // the place in the code I've selected to show
      _main in main.o // the place in the code I've selected to show
      generate_train_file()     in fann_utils.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
make: *** [hPif] Error 1