21. Data Transmission

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

void convert_to_big_endian(uint32_t value, uint8_t arr[4]) {
    // Store most significant byte first
    arr[0] = (value >> 24) & 0xFF;
    arr[1] = (value >> 16) & 0xFF;
    arr[2] = (value >> 8) & 0xFF;
    arr[3] = value & 0xFF;
}

int main() {
    uint32_t value;
    uint8_t arr[4];
    scanf("%u", &value);
    convert_to_big_endian(value, arr);
    for (int i = 0; i < 4; i++) {
        printf("%u", arr[i]);
        if(i<3){
            printf(" ");
        }
    }
    return 0;
}

Big-endian transmission means the most significant byte is sent first.
This format is common in network protocols and cross-platform embedded communications.

Also note: when you pass an array to a function, you’re actually passing a pointer to its first element. So any modification made to arr inside the function will reflect in the main() function — because both refer to the same memory.