What is the meaning of a - b + c ?
Answer: A
Like most operators, + and - are left-associative. When two left-associative operators of the same precedence are adjacent, the left one is done first.
A few languages, such as Smalltalk and Python, do not have precedence and proceed left-to-right. However, all mainstream languages use precedence and associativity as described above; a compiler is required to process a language as defined by the language standard.