/in/foo.c: In function 'MergeSubs':
/in/foo.c:44:17: error: 'nextStart' undeclared (first use in this function)
         start = nextStart + 1;
                 ^~~~~~~~~
/in/foo.c:44:17: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c: In function 'main':
/in/foo.c:50:11: warning: too many arguments for format [-Wformat-extra-args]
     scanf("%d", &n1,&n2);
           ^~~~
/in/foo.c:55:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
     for (int i = 0; i < n2; i++)
     ^~~
/in/foo.c:57:2: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
  MergeSubs(a1, n1);
  ^~~~~~~~~