Integer lifting example

1️⃣ Integers are all in memory 32 A bit , It's just that if it is char Truncation occurs for this type of （ Be careful to convert it into a complement ）
2️⃣ Integer promotion depends on type promotion signed Just add the sign bit unsigned char Just add 0
3️⃣ A positive number 、 back 、 Complement the same

int main()
{
    
	char a = -1;
	signed char b = -1;
	unsigned char c = -1;
	printf("a = %d, b = %d, c = %d", a, b, c);
	return 0;
}

To do this problem, you must first know signed char and unsigned char The scope of the

signed char

unsigned char

So I'm looking at this problem , Use all three %d In the form of printing , So there will be plastic improvement
char a：

signed char and char It is equivalent.

answer -1 , -1, 255

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int main()
{
    
	char a = -128;
	char b = 128;
	printf("%u\n", a);
	printf("%u\n", b);
	return 0;
}

answer ： 4294967168, 4294967168

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int main()
{
    
	int i = -20;
	unsigned int j = 10;
	printf("%d\n", i + j);
	return 0;
}

We need to know the priority order before we do this problem

long double
double
float
unsigned long int
long int
unsigned int
int

Operate in the form of complement , Finally, it is formatted as a signed integer

answer ： -10

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