Compilare: main.cpp: In function 'void solve()': main.cpp:117:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 117 | for(int i = 0; i < c.size(); i++) { | ~~^~~~~~~~~~ main.cpp: In instantiation of 'std::vector<int> FFT<FL>::multiply(std::vector<int>, std::vector<int>) [with FL = double]': main.cpp:116:41: required from here main.cpp:70:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 70 | for(int i = 0; i < a.size(); i++) { | ~~^~~~~~~~~~ main.cpp:75:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 75 | for(int i = 0; i < a.size(); i++) { | ~~^~~~~~~~~~ main.cpp:80:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 80 | for(int i = 0; i < a.size(); i++) { | ~~^~~~~~~~~~