C++函数无法正确调用主函数

现在我确定答案很简单。 我对编码很陌生，似乎无法将函数正确调用到主函数中。 以下是我试图实现的目标：该函数应该将用户输入与另一个随机生成数字的函数进行比较，重点是将随机化和用户输入保持在两个不同的函数中。 这是代码。 谢谢大家！

#include <random>
#include <string>
using namespace std;
std::random_device seed;
std::mt19937 mersenneTwister(seed());
int RandomInt(int min, int max);
int GuessNum(int NumGuessed);
int main() 
{
int MagicNumber = RandomInt(1, 100);
int GuessNum(int MagicNumber);



}
int RandomInt(int min, int max)
{
std::uniform_int_distribution<int> distribution(min, max);
return distribution(mersenneTwister);
}
int GuessNum(int NumGuessed)
// supposed to ask for user input in main?
{
int guess = 0;
cout << "Guess what number did the computer generaten";
cin >> guess;
if (guess == NumGuessed)
{
cout << "You winn";
}
else if (guess > NumGuessed)
{
cout << "Highern";
}
else if (guess > NumGuessed)
{
cout << "Lowern";
}
else if (guess < 1 || guess > 100) {
cout << "invalid inputn";
}
return 0;
}