Trying to connect other cpp files. When adding, it gives errors:

LNK2005 "__int64 __cdecl powmod(__int64,__int64,__int64)" (?powmod@@YA_J_J00@Z) уже определен LNK2005 "__int64 __cdecl powmod(__int64,__int64,__int64)" (?powmod@@$$FYA_J_J00@Z) уже определен в Pollard.obj all_metods LNK1169 обнаружен многократно определенный символ - один или более all_metods

Shenks.cpp file code:

 #include <iostream> #include <math.h> #include "methods.h" #include <map> using namespace std; __int64 powmod(__int64 a, __int64 b, __int64 m) { __int64 res = 1; while (b > 0) if (b & 1) { res = (res * a) % m; --b; } else { a = (a * a) % m; b >>= 1; } return res % m; } __int64 Shenks(__int64 a,__int64 b,__int64 m) { __int64 n = (__int64)sqrt(m) + 1; // __int64 *r; // r = new __int64[n]; map<__int64,__int64> vals; for (__int64 i = n; i >= 1; --i) vals[powmod(a, i * n, m)] = i; for (__int64 i = 0; i <= n; ++i) { __int64 cur = (powmod(a, i, m) * b) % m; if (vals.count(cur)) { __int64 ans = vals[cur] * n - i; if (ans < m) return ans; } } return -1; }

Code file Pollard.cpp:

 #include <iostream> #include "methods.h" #include <vector> using namespace std; __int64 powmod(__int64 a, __int64 b, __int64 m) { __int64 res = 1; while (b > 0) if (b & 1) { res = (res * a) % m; --b; } else { a = (a * a) % m; b >>= 1; } return res % m; } __int64 gcdex(__int64 a, __int64 b, __int64 &x, __int64 &y) { if (b == 0) { x = 1; y = 0; return a; } __int64 x1, y1; __int64 d1 = gcdex(b, a % b, x1, y1); x = y1; y = x1 - (a / b) * y1; return d1; } __int64 ReverseElement(__int64 a, __int64 N) { __int64 x, y, d; d = gcdex(a, N, x, y); if (d != 1) { return 1; } else return x; } __int64 NOD(__int64 a, __int64 b) { while (a > 0 && b > 0) if (a > b) a %= b; else b %= a; return a + b; } __int64 phi(__int64 n) { __int64 result = n; for (__int64 i = 2; i*i <= n; ++i) if (n % i == 0) { while (n % i == 0) n /= i; result -= result / i; } if (n > 1) result -= result / n; return result; } __int64 Pollard(__int64 a, __int64 b, __int64 p) { vector<__int64> z(214783640), u(214783640), v(214783640); z[0] = 1; __int64 ph = phi(p); __int64 ak = 0, ev = 0, eu = 0, nod, chk; __int64 p1 = p - 1; __int64 x = 0; for (__int64 i = 0; i < p; i++) { if (z[i] % 3 == 1) { z[i + 1] = b * z[i] % p; u[i + 1] = u[i] % ph; v[i + 1] = (v[i] + 1) % ph; } if (z[i] % 3 == 2) { z[i + 1] = z[i] * z[i] % p; u[i + 1] = 2 * u[i] % ph; v[i + 1] = 2 * v[i] % ph; } if (z[i] % 3 == 0) { z[i + 1] = a * z[i] % p; u[i + 1] = (u[i] + 1) % ph; v[i + 1] = v[i] % ph; } if (*find(z.begin(), z.begin() + i, z[i + 1]) != *(z.begin() + i)) { ak = distance(z.begin(), find(z.begin(), z.begin() + i, z[i + 1])); ev = v[ak] - v[i + 1]; if (ev < 0) ev += p1; eu = u[i + 1] - u[ak]; if (eu < 0) eu += p1; nod = NOD(ev, p1); ev /= nod; eu /= nod; p1 /= nod; chk = ReverseElement(ev, p1); if (chk < 0) chk += p1; x = chk*eu%p1; if (powmod(a, x, p) != b) x += p1; break; } } return x; }

As I understand it, because the same powmod function is used. How to correct?

  • You do not specify exactly where you are trying to add cpp files. It looks like you need to finish the cpp file in the build system - KoVadim
  • He he he he ... "BNPNYA VHRYUK?" - AnT
  • Yes, and the reason is that someone forgot to add guard in the header file (ifdef or pragma once) or just accumulate the same. - KoVadim
  • @KoVadim And how could the guards here / can help? - AnT
  • if you put them right ... - KoVadim

1 answer 1

Yes, it is in the double definition of powmod .

If it is known that in both cases exactly the same function is needed (as at the moment)

  1. If the function is external, i.e. maybe other modules of the project are also needed, then remove one, leave another.
  2. If the function is purely internal to the module, then, perhaps, for the sake of preserving the independence of the modules, it is worth keeping both copies, but declare them static (or enclose an unnamed namespace). Do the same with other inherent functions.

If these functions coincided purely by chance, then rename them to eliminate the coincidence of names.