What is side effect in C?
问题 Wikipedia says that: In computer science, an operation, function or expression is said to have a side effect if it modifies some state variable value(s) outside its local environment, that is to say has an observable effect besides returning a value (the main effect) to the invoker of the operation. But how can we access a variable outside its local environment, can anyone explain this situation, side effect, main effect and sequence point comprehensibly? 回答1: A function is (should be) a