(不)正解

#include<iostream>
using namespace std;
int main(){
	cout<<"c=299792458";
}

正解

#include <iostream>
using namespace std;
signed main()
{
	const int C = 299792458;//m/s
	int ans = 0;
	for (int i = 1; i <= C; ++i)
	{
		++ans;
	}
	cout << "c=" << ans;
	return 0;
}