Compilare: main.cpp: In function 'int main()': main.cpp:18:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<nr.size();++i){ ~^~~~~~~~~~ main.cpp:19:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=i;j<nr.size();++j){ ~^~~~~~~~~~ main.cpp:20:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=j;k<nr.size();++k){ ~^~~~~~~~~~ main.cpp:10:27: warning: unused variable 'ok' [-Wunused-variable] int n,sum,i,j,k,val,s,ok=0; ^~