Compilare: main.cpp: In function 'int main()': main.cpp:20:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < nr.size(); ++i) { ~~^~~~~~~~~~~ main.cpp:21:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = i; j < nr.size(); ++j) { ~~^~~~~~~~~~~ main.cpp:22:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = j; k < nr.size(); ++k) { ~~^~~~~~~~~~~ main.cpp:19:7: warning: unused variable 'x' [-Wunused-variable] int x,y,z; ^ main.cpp:19:9: warning: unused variable 'y' [-Wunused-variable] int x,y,z; ^ main.cpp:19:11: warning: unused variable 'z' [-Wunused-variable] int x,y,z; ^