std::strcmp(3)

💅 std::strcmp(3) — the C++ Standard Library page, but make it make sense

okay so bestie, this is std::strcmp from the C++ Standard Library, and honestly? she's the blueprint. let's get into it 🎀

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✨ NAME ✨

std::strcmp — yeah. that's it. that's the name. std::strcmp. iconic, no notes 💅

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🌸 SYNOPSIS 🌸

Defined in header <cstring>:

int strcmp( const char* lhs, const char* rhs );

So what does she do? She compares two null-terminated byte strings lexicographically. That's the whole gig 🦋

And here's the part you actually need to internalise: the sign of the result is the sign of the difference between the values of the first pair of characters that differ in the two strings — and both of those characters get interpreted as unsigned char. so like, it's not vibes-based, it's "first difference decides everything" energy ✨

⚠️ ok real talk for a sec: the behavior is undefined if lhs or rhs are not pointers to null-terminated strings. undefined. not "a little weird". not "she'll figure it out". undefined behavior, bestie 😭 do not test her.

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🧚 PARAMETERS 🧚

• lhs, rhs — pointers to the null-terminated byte strings you want to compare. that's them. two little string pointers, ready to be judged 🫶

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👑 RETURN VALUE 👑

• Negative value — if lhs appears before rhs in lexicographical order. she comes first, periodt.
• Zero — if lhs and rhs compare equal. twins. same energy. 💖
• Positive value — if lhs appears after rhs in lexicographical order. she's in her late-arrival era 🌈

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🔥 EXAMPLE 🔥

run this code 👇

#include <algorithm>
#include <cstring>
#include <iostream>
#include <vector>

int main()
{
    std::vector<const char*> cats{"Heathcliff", "Snagglepuss", "Hobbes", "Garfield"};
    std::sort(cats.begin(), cats.end(), [](const char* strA, const char* strB)
    {
        return std::strcmp(strA, strB) < 0;
    });

    for (const char* cat : cats)
        std::cout << cat << '\n';
}

like... sorting cats. with std::strcmp. the range-based for at the end is chef's kiss 😭💜

⭐ Output ⭐

Garfield
Heathcliff
Hobbes
Snagglepuss

alphabetical cat slay. Garfield said "I'm the main character" and honestly? she ate 💅

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🦋 SEE ALSO 🦋

• strncmp — compares a certain number of characters from two strings (function)
• wcscmp — compares two wide strings (function)
• memcmp — compares two buffers (function)
• strcoll — compares two strings in accordance to the current locale (function)
• C documentation for strcmp — the og. the source material. iykyk 📚

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okay that's the whole page, no cap, every flag-and-fact intact 🙈 lowkey one of the cleanest functions out there — just remember the unsigned char thing and the "must be null-terminated or it's undefined behavior" thing and you're golden 🧚‍♀️

this gem is brought to you by http://cppreference.com, version 2024.06.10 — go drink some water and go touch a null terminator 🩵🍓