C Program to Convert Decimal to Hexadecimal

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 ...

✅ C Program to Convert Decimal Number to Hexadecimal

#include <stdio.h>

int main() {
    int num;

    printf("Enter a decimal number: ");
    scanf("%d", &num);

    printf("Hexadecimal: %X\n", num);   // %X prints in uppercase A–F
    printf("Hexadecimal (lowercase): %x\n", num); // %x prints in lowercase a–f

    return 0;
}

📘 Explanation:

This program converts a decimal number into its hexadecimal representation using the printf format specifiers:

%X → prints the hexadecimal value in uppercase (A–F).
%x → prints the hexadecimal value in lowercase (a–f).
For example, decimal 255 will be displayed as FF and ff.

🧾 Sample Output:

Enter a decimal number: 255
Hexadecimal: FF
Hexadecimal (lowercase): ff

🔑 Keywords:

C program decimal to hexadecimal, printf %X and %x, decimal to hex conversion in C, hexadecimal number system C program, beginner C examples

📌 Hashtags:

#CProgramming #HexadecimalConversion #DecimalToHex #CExamples #CodingForBeginners

🔍 Search Description:

This C program converts a decimal number into hexadecimal using printf format specifiers %X and %x. It displays both uppercase and lowercase hexadecimal outputs with examples.

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