Compilare: main.cpp: In function 'int main()': main.cpp:18:14: warning: converting to non-pointer type 'char' from NULL [-Wconversion-null] s[l]=NULL; ^~~~ main.cpp:22:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<(strlen(s)-1)&&ok==0){ ~^~~~~~~~~~~~~~ main.cpp:11:18: warning: unused variable 'k' [-Wunused-variable] int t,i,l,ok,k,ceva,j; ^ main.cpp:11:20: warning: variable 'ceva' set but not used [-Wunused-but-set-variable] int t,i,l,ok,k,ceva,j; ^~~~