Java基本数字促销
例子
static void testNumericPromotion() { char char1 = 1, char2 = 2; short short1 = 1, short2 = 2; int int1 = 1, int2 = 2; float float1 = 1.0f, float2 = 2.0f; // char1 = char1 + char2; //错误:无法从int转换为char; // short1 = short1 + short2; //错误:无法从int转换为short; int1 = char1 + char2; //char被提升为int。 int1 = short1 + short2; //short被提升为int。 int1 = char1 + short2; //char和short都被提升为int。 float1 = short1 + float2; //空头被提升为浮动。 int1 = int1 + int2; //int不变。 }