设变量已正确定义，以下是合法的switch语句。

switch(choice){         \n    case choice == 1: price = 3.0; break; \n    case choice == 2: price = 2.5; break;\n    case choice == 3: price = 4.0; break;\n    case choice == 4: price = 3.5; break;\n    default: price = 0.0; break;\n}