C language: find the number of 1 in binary stored in memory as an integer

int main()
{
    
	// For negative numbers, we count the number of complements 1
	// such as -1
	// primary ：10000000 00000000 00000000 00000001
	// back ：11111111 11111111 11111111 11111110
	// repair ：11111111 11111111 11111111 11111111
	//-1 Binary stored in memory 1 The number of 32
	int a = 0;
	printf(" Please enter the integer you want to test ：");
	scanf("%d", &a);
	int tmp = a;
	int count = 0;
	if (a >= 0)
	{
    
		while (a)
		{
    
			if (a & 1) {
    // You can judge the current a And then finally 1 still 0
				count++;
			}
			a = a >> 1;
		}
	}
	else
	{
    
		// Move the negative number right , My compiler shifts arithmetic right （ Most compilers shift arithmetic right ）
		// Arithmetic is moving right , Rightmost number discard , Fill in the sign on the left , Because it is negative, that is, complement 1
		// If you still use it here while(a) It will continue in an endless cycle , Because the left side will always fill 1
		// But we know that plastic surgery is 32 Bits stored in memory , We cycle 32 Next time 
		for (int i = 0;i < 32;i++)
		{
    
			if (a & 1) {
    // You can judge the current a And then finally 1 still 0
				count++;
			}
			a = a >> 1;
		}
	}
	printf("%d Binary stored in memory 1 The number of %d", tmp,count);
	return 0;
}

Screenshot of Niuke passing the test

Links to related topics ： Binary 1 The number of