Compilare: user.cpp: In function ‘int main()’: user.cpp:14:10: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[n]=NULL; ^ user.cpp:8:37: warning: variable ‘b’ set but not used [-Wunused-but-set-variable] int n=0,k=0,i,top=-1,k2=0,a[5000],b[5000],max=0,ok,k1=0,nr,z=0,k4=0,c[5000],k5,l,r,max1=0; ^ user.cpp:8:79: warning: unused variable ‘k5’ [-Wunused-variable] int n=0,k=0,i,top=-1,k2=0,a[5000],b[5000],max=0,ok,k1=0,nr,z=0,k4=0,c[5000],k5,l,r,max1=0; ^ user.cpp:8:82: warning: unused variable ‘l’ [-Wunused-variable] int n=0,k=0,i,top=-1,k2=0,a[5000],b[5000],max=0,ok,k1=0,nr,z=0,k4=0,c[5000],k5,l,r,max1=0; ^ user.cpp:8:84: warning: unused variable ‘r’ [-Wunused-variable] int n=0,k=0,i,top=-1,k2=0,a[5000],b[5000],max=0,ok,k1=0,nr,z=0,k4=0,c[5000],k5,l,r,max1=0; ^