Little Endian to Big Endian

Code

#include <stdio.h>
#include <stdint.h>

uint32_t convert_endian(uint32_t value) {
    // Write logic to swap bytes
    return ((value >> 24) & 0x000000FF) |
           ((value >> 8) & 0x0000FF00) |
           ((value << 8) & 0x00FF0000)|
           ((value << 24) & 0xFF000000);
}

int main() {
    uint32_t val;
    scanf("%u", &val);
    printf("%u", convert_endian(val));
    return 0;
}

Solving Approach
To convert a value from little-endian to big-endian, you're reversing the byte order — a common task in embedded systems when communicating across architectures.

🪜 Solving Algorithm: Little to Big Endian (32-bit)

Let’s say you have a 32-bit value stored in little-endian format:

uint32_t val = 0x12345678;

In memory (little-endian):

Byte[0] = 0x78  
Byte[1] = 0x56  
Byte[2] = 0x34  
Byte[3] = 0x12

To convert to big-endian, you want:

Byte[0] = 0x12  
Byte[1] = 0x34  
Byte[2] = 0x56  
Byte[3] = 0x78

✅ Step-by-Step Algorithm

1. Extract each byte using bitwise AND and shifts:
   • byte0 = (val >> 24) & 0xFF
   • byte1 = (val >> 16) & 0xFF
   • byte2 = (val >> 8) & 0xFF
   • byte3 = val & 0xFF

2. Reassemble in reversed order:

   big_endian_val = (byte3 << 24) |
                    (byte2 << 16) |
                    (byte1 << 8)  |
                    (byte0);
   

🧠 Embedded-Friendly C Code

uint32_t little_to_big_endian(uint32_t val) {
    return ((val >> 24) & 0x000000FF) |
           ((val >> 8)  & 0x0000FF00) |
           ((val << 8)  & 0x00FF0000) |
           ((val << 24) & 0xFF000000);
}

🧪 Example

Input: 0x12345678
Output: 0x78563412 (big-endian representation)