Vast majority of resource about contracts deal with using them in web applications with JavaScript web3.
But how you interact with contracts (create, call them, make transactions) in a C++ application?
[Ethereum] How to interact with contracts in C++ application
contract-deploymentdapps
Related Solutions
Yes, contracts have nonces. EIP 161 made the contract nonce start at 1, and before EIP 161 the nonce would start at 0. A nonce of a contract is only incremented when that contract creates another contract (@zanzu's YP reference). When a contract invokes a function on another contract, a so called "internal transaction", the nonce is not incremented.
The nonce can be obtained by using web3.eth.getTransactionCount. There is no built-in method for a contract to access an account's nonce, including its own. (A contract could use its storage to keep track of its own nonce.)
To make it clear, there are only 2 types of accounts in Ethereum and they all have the same 4 "physical" properties: nonce, balance (in wei), hash of storage trie root, and code. The only "physical" difference is that a contract has non-zero code.
In terms of behavior, there are some more differences between contracts and usual accounts. The incrementing of the nonce is one behavioral difference; another major one is Where is the private key for a contract stored?
To clarify "Usual accounts have a nonce that is increased with every transaction", the nonce of a non-contract account is only incremented when that account originates a transaction (when it's the sender from account). When an account is the recipient (the to account), its nonce is not incremented.
Lightwallets are basically modules that provide the functionality for signing transactions locally on your PC or in your browser. These signed transaction are sent via RPC to a remote full node, where they are added to the blockchain.
So light wallets do have access to the entire chain and all contracts without having to download the chain data, not even partially on request.
Interaction with the contracts is therefore through the remote node, and the remote node always has access to the most recent data, as long as it is in sync.
Metamask illustrates nicely how a light wallet works in its Architecture section of its github readme.
Best Answer
Regardless of the language, you can always resort to the JSONRPC to interact with the network.