foo.cc: In function ‘int main()’:
foo.cc:5:11: warning: unused variable ‘l’ [-Wunused-variable]
    5 | int n1,n2,l=0,tep=0;
      |           ^
foo.cc:7:17: warning: unused variable ‘c’ [-Wunused-variable]
    7 | int a[n1],b[n2],c[n1+n2];
      |                 ^