How to distinguish big and small endian in C language

Shocked!It is so easy to distinguish big and small end in C language

C language has an interview question called distinguishing whether a computer is big endian or little endian.

The big endian mode means that the high byte of the data is stored in the low address of the address space, and the low byte of the data is stored in the high address of the address space

Little-endian mode means that the high byte of the data is stored in the high address of the address space, and the low byte of the data is stored in the low address of the address space

How to tell?code above

#includeint main(void){short a=0x01;//0x.. is a hexadecimal number, 0x01 is written as a short type is 00000000 00000001char *c=&a;//When accessing the address in the variable, follow the access rules of char, if it is big endian, then *c=0if((*c)==0){printf("big\n");}else{printf("small\n");}return 0;}

??? Are you confused?I believe that people with a bit of basic knowledge must know this

#include typedef union Un{char c;short i;}un;int main(){un n;n.i=1;if (1 == n.c){printf("small\n");}else{printf("big\n");}return 0;}

This code should not need to be explained, there are a lot of them on the Internet.So, let me explain the code above.

As the comment says, the variable a is stored in the address space like this:

00000000 00000001

The address stored in the pointer type variable p is the address of a, but when reading with the char access rule, only read

00000000

or

00000001

One of

.If the read is 00000000, it means that the high byte is stored in the low address of the address space, otherwise the low byte is stored in the low address of the address space.From this, you can judge the size end, is it very simple?

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