bitCount()
ファイルに名前が付けられた関数を記述したいと思います。この関数bitcount.c
は、符号なし整数引数のバイナリ表現のビット数を返します。
これが私がこれまでに持っているものです:
#include <stdio.h>
int bitCount (unsigned int n);
int main () {
printf ("# 1-bits in base 2 representation of %u = %d, should be 0\n",
0, bitCount (0));
printf ("# 1-bits in base 2 representation of %u = %d, should be 1\n",
1, bitCount (1));
printf ("# 1-bits in base 2 representation of %u = %d, should be 16\n",
2863311530u, bitCount (2863311530u));
printf ("# 1-bits in base 2 representation of %u = %d, should be 1\n",
536870912, bitCount (536870912));
printf ("# 1-bits in base 2 representation of %u = %d, should be 32\n",
4294967295u, bitCount (4294967295u));
return 0;
}
int bitCount (unsigned int n) {
/* your code here */
}
さて、これを実行すると、次のようになります。
# 1-bits in base 2 representation of 0 = 1, should be 0
# 1-bits in base 2 representation of 1 = 56, should be 1
# 1-bits in base 2 representation of 2863311530 = 57, should be 16
# 1-bits in base 2 representation of 536870912 = 67, should be 1
# 1-bits in base 2 representation of 4294967295 = 65, should be 32
RUN SUCCESSFUL (total time: 14ms)
正しいビット数を返しません。
Cの符号なし整数引数のバイナリ表現のビット数を返すための最良の方法は何ですか?