後自增（減）的結果不是左值

#include <cstdio> int main() { int foo = 5; void* p = NULL; printf_s("Address of foo is 0x%p. /r/n", &foo); // 0x0012FF60 p = &(++foo); printf_s("Address of ++foo is 0x%p. /r/n", p); // 0x0012FF60 p = &(--foo); printf_s("Address of --foo is 0x%p. /r/n", p); // 0x0012FF60 p = &(foo++); // error C2102: '&' requires l-value ++(foo++); // error C2105: '++' needs l-value (foo++)++; // error C2105: '++' needs l-value // Note: (foo++)++ is identical to foo++++ --(foo--); // error C2105: '--' needs l-value (foo--)--; // error C2105: '--' needs l-value // Note: (foo--)-- is identical to foo---- return 0; }