cpi.rs

// calling token program to burn some tokens
invoke(
  &spl_token::instruction::burn(
      &spl_token::id(),
      user_token_account_ai.key,
      vending_machine_mint.key,
      &user.key,
      &[],
      price,
  )?,
  &[user_token_account_ai.clone(), vending_machine_mint.clone(), user.clone()],
)?;
// allocating data for a mint account
invoke_signed(
    &system_instruction::create_account(
        user.key,
        pool_mint_ai.key,
        rent::Rent::get()?.minimum_balance(mint_data_len),
        mint_data_len as u64,
        &spl_token::id(),
    ),
    &[user.clone(), pool_mint_ai.clone(), system_program.clone()],
    &[pool_mint_seeds],
)?;