Compilare: user.cpp:3:0: warning: "ULLONG_MAX" redefined #define ULLONG_MAX ^ In file included from /usr/lib/gcc/x86_64-linux-gnu/5/include-fixed/limits.h:168:0, from /usr/lib/gcc/x86_64-linux-gnu/5/include-fixed/syslimits.h:7, from /usr/lib/gcc/x86_64-linux-gnu/5/include-fixed/limits.h:34, from user.cpp:2: /usr/include/limits.h:137:0: note: this is the location of the previous definition # define ULLONG_MAX (LLONG_MAX * 2ULL + 1) ^ user.cpp: In function ‘int main()’: user.cpp:9:42: warning: unused variable ‘M’ [-Wunused-variable] int v,n,l=1,maxlinie=-1,linie,i,j,S1,M,p,r; ^ user.cpp:9:44: warning: unused variable ‘p’ [-Wunused-variable] int v,n,l=1,maxlinie=-1,linie,i,j,S1,M,p,r; ^ user.cpp:9:46: warning: unused variable ‘r’ [-Wunused-variable] int v,n,l=1,maxlinie=-1,linie,i,j,S1,M,p,r; ^ user.cpp:32:16: warning: ‘linie’ may be used uninitialized in this function [-Wmaybe-uninitialized] fout<<linie; ^