Solved: c detect endianness

Endianness refers to the sequential order in which bytes are arranged into larger numerical values when stored in memory or during transmission. The two main types of endianness that exist are big endian and little endian. Big endian is the most significant byte in the smallest address and little endian is the least significant byte in the smallest address. In C programming, endianness matters when you’re reading binary data directly without using the extraction operators. Check out the solution and a detailed professional breakdown of the code provided to detect the endianness of a system. Additionally, you will learn about the significance of the libraries and functions involved in solving this seemingly complex problem.


int main() 
   unsigned int i = 1;
   char *c = (char*)&i;
   if (*c)   
       printf("Little endian");
       printf("Big endian");
   return 0;

Step-by-Step Explanation of the Code

The code snippet provided is written in C, a general-purpose, procedural programming language which will determine the endianness of a system.

Firstly, let’s analyze the #include this is a pre-processor command that includes standard input/output library. This library is necessary for multiple functionalities like “printf” and “getchar” to work on most systems.

Key Function and Variables

Next, the main function is declared. This is the entry point of any C program. Within this function, an unsigned integer i is declared and initialized to 1, and a char pointer ‘c’ is declared and initialized to the address of i.

The conditional statement that follows checks whether the first byte in the char pointed to by ‘c’ is 1 or 0. If it’s 1, the system is little endian, otherwise it is big endian.

This conditional check forms the core of the program and is the logic we use to detect the system’s endianness.

The printf function is used to either display “Little endian” or “Big endian” based on the result of our conditional check. It belongs to the stdio.h library and is used for output formatting.

Understanding Libraries

The stdio.h is a standard library in C programming that includes definitions of types, macros and functions for tasks such as input/output operations, file access, string handling, etc. It plays a vital role in displaying output to the screen.

Understanding Data Types and Pointers

In C programming, pointers are variables that store addresses of other variables. Here, ‘char *c’ is a pointer to a character.

The bitwise operator ‘&’ is used to get the address of ‘i’ and assign it to ‘c’. The purpose of this operation is to get the byte level representation of the integer variable ‘i’ to check its endianness.

To summarize, detecting a system’s endianness is crucial in certain low-level programming tasks, and this code provides an simple method to check the endianness using C programming language. Furthermore, understanding the libraries, functions, data types and pointers applied in this code piece will lay a strong foundation for your journey in C programming.

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