> ## Documentation Index
> Fetch the complete documentation index at: https://docs.theblockchainlibrary.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Anchor Program — Solana Counter

> A Solana counter program using the Anchor framework with PDA-based state storage.

# Anchor Program — Solana Counter

A Solana counter program using the Anchor framework with PDA-based state storage.

A Solana counter program using the Anchor framework with PDA-based state storage.

## Explanation

Anchor is Solana's most popular framework. The #\[program] module defines instruction handlers. Accounts are validated via #\[derive(Accounts)]. PDA seeds ensure deterministic addresses. The space calculation (8 + 8) accounts for the discriminator and the u64 field.

## Code

```rust theme={null}
use anchor_lang::prelude::*;

#[program]
pub mod counter {
    use super::*;

    pub fn initialize(ctx: Context<Initialize>) -> Result<()> {
        let counter = &mut ctx.accounts.counter;
        counter.count = 0;
        Ok(())
    }

    pub fn increment(ctx: Context<Increment>) -> Result<()> {
        let counter = &mut ctx.accounts.counter;
        counter.count += 1;
        Ok(())
    }
}

#[derive(Accounts)]
pub struct Initialize<'info> {
    #[account(mut)]
    pub user: Signer<'info>,
    #[account(
        init,
        space = 8 + 8,
        payer = user,
        seeds = [b"counter", user.key().as_ref()],
        bump
    )]
    pub counter: Account<'info, Counter>,
    pub system_program: Program<'info, System>,
}

#[derive(Accounts)]
pub struct Increment<'info> {
    #[account(mut)]
    pub counter: Account<'info, Counter>,
}

#[account]
pub struct Counter {
    pub count: u64,
}
```

***

**Canonical knowledge ID:** `code-example:anchor-program-solana-counter`