CHECK IF SYSTEM IS LITTLE ENDIAN OR BIG ENDIAN IN C

October 15, 2026

Solve LeetCode 3 Longest Substring Without Repeating Characters in C++ using the sliding window

Longest Substring Without Repeating Characters in C++ LeetCode 3 · sliding window · last index array Table of Contents Problem Statement Approach Algorithm C++ Program Input Sample Output Output Explanation Dry Run Flow of Execution Time Complexity Space Complexity Applications Key Points Interview Questions Frequently Asked Questions Conclusion Problem Statement 3. Longest Substring Without Repeating Characters Given a string s , find the length of the longest substring that contains no repeating characters. A substring is a continuous part of the string, so "pwke" is a subsequence of "pwwkew" but not a substring. Approach We use a sliding window . The window is the part of the string between start and end , and we always keep it free of repeated characters. An array lastIndex of size 128 remembers the most recent position of every ASCII ...

✅ CHECK SYSTEM ENDIANNESS IN C

#include <stdio.h>

int main() {
    int x = 0x12AB6578;
    char *ptr = (char *)&x;

    if (*ptr == 0x78) {
        printf("System is Little Endian:\n");
    } else {
        printf("System is Big Endian:\n");
    }

    return 0;
}

🧠 Explanation:

This program determines the endianness of the system.

A hexadecimal number is stored in memory: 0x12AB6578.
The memory address of x is typecast to a char*, pointing to the least significant byte.
If the first byte contains 0x78, the system is Little Endian (least significant byte stored first).
Otherwise, the system is Big Endian.

🖥️ Sample Output:

System is Little Endian:

🔑 Keywords:

C program to check endianness, little endian vs big endian, pointer typecasting in C, memory representation in C, system architecture test.

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Solve LeetCode 3 Longest Substring Without Repeating Characters in C++ using the sliding window