Compilare: main.cpp: In function 'void fft(std::vector<Complex>&, int)': main.cpp:94:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < pol.size(); ++i) ~~^~~~~~~~~~~~ main.cpp:98:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int len = 1; len < pol.size(); len*= 2) { ~~~~^~~~~~~~~~~~ main.cpp:101:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int pos = 0; pos < pol.size(); pos+= len * 2) { ~~~~^~~~~~~~~~~~ main.cpp:112:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < pol.size(); ++i) ~~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:130:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (v1.size() <= t) ~~~~~~~~~~^~~~ main.cpp:136:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (v2.size() <= t) ~~~~~~~~~~^~~~ main.cpp:142:32: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses] while (v1.size() & v1.size() - 1) ~~~~~~~~~~^~~ main.cpp:148:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v1.size(); ++i) ~~^~~~~~~~~~~ main.cpp:152:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v1.size(); ++i) ~~^~~~~~~~~~~ main.cpp: In member function 'char InParser::nextch()': main.cpp:16:28: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, BMAX, fi); ^