__builtin_parity (unsigned int)

奇偶校驗，判斷二進制1的個數是奇數返回1，偶數返回0

int n = 7; int m = 15; cout << "n = " << n << " " << __builtin_parity(n) << endl; // 輸出 1 cout << "m = " << m << " " << __builtin_parity(m) << endl; // 輸出 0

__builtin_popcount (unsigned int)

二進制1的個數

int n = 7; int m = 15; cout << "n = " << n << " " << __builtin_popcount(n) << endl; // 輸出 3 cout << "m = " << m << " " << __builtin_popcount(m) << endl; // 輸出 4

__builtin_ffs (unsigned int)

二進制最后1的位置

int n = 1; int m = 4; cout << "n = " << n << " " << __builtin_ffs(n) << endl; // 輸出 1 cout << "m = " << m << " " << __builtin_ffs(m) << endl; // 輸出 3

__builtin_ctz (unsigned int)

二進制末尾0的個數

int n = 1; int m = 4; cout << "n = " << n << " " << __builtin_ctz(n) << endl; // 輸出 0 cout << "m = " << m << " " << __builtin_ctz(m) << endl; // 輸出 2

__builtin_clz (unsigned int)

二進制前導0的個數

int n = 1; int m = 4; cout << "n = " << n << " " << __builtin_clz(n) << endl; // 輸出 31 cout << "m = " << m << " " << __builtin_clz(m) << endl; // 輸出 29

總結

以上是生活随笔為你收集整理的GCC内置位运算的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。