Compilare: main.cpp: In function 'std::vector<Complex> FFT(std::vector<Complex>&, int)': main.cpp:52:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < A.size(); i += 2){ ~~^~~~~~~~~~ main.cpp:55:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < A.size(); i += 2) ~~^~~~~~~~~~ main.cpp:61:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < A.size() / 2; i++){ ~~^~~~~~~~~~~~~~ main.cpp: In function 'void Solve(std::vector<double>, std::vector<double>)': main.cpp:99:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < A.size(); i++) ~~^~~~~~~~~~ main.cpp:106:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < B.size(); i++) ~~^~~~~~~~~~ main.cpp:119:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < X.size(); i++){ ~~^~~~~~~~~~ main.cpp:123:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < C.size(); i++){ ~~^~~~~~~~~~ main.cpp: In function 'void Read()': main.cpp:69:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ main.cpp:77:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &r); ^ main.cpp:83:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &M); ^ main.cpp:86:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &r); ^ main.cpp: In function 'int main()': main.cpp:136:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("bacterii2.in", "r", stdin); ^ main.cpp:137:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("bacterii2.out", "w", stdout); ^ main.cpp:138:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &T); ^