Main.cc: In function 'int main()':
Main.cc:5:12: error: redeclaration of 'int n'
int n=0,m,n;
^
Main.cc:5:6: note: 'int n' previously declared here
int n=0,m,n;
^
Main.cc:5:10: warning: unused variable 'm' [-Wunused-variable]
int n=0,m,n;
^