The error means that the compiler was looking for a name (and identifier), but instead, it found a number (ordinal const).
As for your code, if I copy the code you provided, it compiles and runs.
Your logic, however, does not work correctly for all scenarios.
For instance, for the input [1, 2, 3] your program does not find the largest number (3).
Review the last if statement to fix the problem.