Compilare: user.cpp: In function ‘int main()’: user.cpp:63:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 0; j < comps.size(); ++j) if(j + 1 != where[i]) mxSize = max(mxSize, (int)comps[j].size()); ^ user.cpp:68:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 0; j < comps.size(); ++j) { ^ user.cpp:70:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k = 0; k < comps[j].size(); ++k) mul(a[comps[j][k]], primes[k]); ^ user.cpp:53:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("coprime.in", "r", stdin); ^ user.cpp:54:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("coprime.out", "w", stdout); ^ user.cpp:55:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(scanf("%d %d", &n, &m); m; --m) scanf("%d %d", &i, &j), edg[i][j] = edg[j][i] = 1; ^ user.cpp:55:88: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(scanf("%d %d", &n, &m); m; --m) scanf("%d %d", &i, &j), edg[i][j] = edg[j][i] = 1; ^