Compilare: user.cpp: In function ‘int main(int, const char**)’: user.cpp:43:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = 0; k < v[size].size(); ++k) ^ user.cpp:55:72: warning: operation on ‘frec[(((int)a[j]) + -97)]’ may be undefined [-Wsequence-point] frec[a[j] - 'a'] = frec[a[j] - 'a'] = v[size][k][j]; ^ user.cpp:24:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("criptare2.in", "r", stdin); ^ user.cpp:25:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("criptare2.out", "w", stdout); ^ user.cpp:29:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ", &n); ^ user.cpp:32:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", a); ^ user.cpp:36:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ", &m); ^ user.cpp:39:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", a); ^