Error(s):

1079746494/source.c: In function ‘main’:
1079746494/source.c:12:9: warning: unused variable ‘l’ [-Wunused-variable]
     int l=6;
         ^
1079746494/source.c:11:9: warning: unused variable ‘k’ [-Wunused-variable]
     int k=5;
         ^
1079746494/source.c: In function ‘add2’:
1079746494/source.c:24:17: error: ‘k’ undeclared (first use in this function)
     printf("%d",k+l);
                 ^
1079746494/source.c:24:17: note: each undeclared identifier is reported only once for each function it appears in
1079746494/source.c:24:19: error: ‘l’ undeclared (first use in this function)
     printf("%d",k+l);
                   ^