int main()
{
int mun = 0;
int i = 0;
int count = 0;
scanf("%d", &mun);
for ( i = 0; i < 32; i++)
{
if (1 == ((mun >> i) & 1))
count++;
}
printf("%d ", count);
return 0;
}
原文：https://blog.51cto.com/14893161/2520734