# Climbing higher

By [Yajas Sardana](https://paragraph.com/@yajas-sardana) · 2023-02-16

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**Progress Report:**

**Challenge 2: 🏵 Token Vendor**

*   The challenged made me dive deeper into transfer of tokens across contracts.
    
*   The most new and interesting part was understanding approval flows, as to how tokens can be used to redeem a commodity like an NFT or even Eth.
    
*   How to check the total eth balance of a contract: **address(this).balance**
    
*   Learnt about and used `transfer` and `transferFrom` functions and understood the different between the two.
    
*   Understood the concept of ownership and its transfer to another contract, so as to enable further inter-contract transfers.
    

**Challenge 3: 🎲 Dice Game**

*   Learnt about block-hashes and why blocks by default don’t support randomness.
    
*   Read up on and used the `keccak256` hash function to create a randomisation mechanism.
    
*   Understood the concept of sending ether along with function calls if that function is payable, for example sending 0.002 eth while calling `rollDice` .
    

**Link to assignments:**

**Challenge 2: 🏵 Token Vendor**

[https://jittery-eggs.surge.sh/](https://jittery-eggs.surge.sh/)

[https://goerli.etherscan.io/address/0x135cb207b6453c94da602e8a777d1b634f61b3b4](https://goerli.etherscan.io/address/0x135cb207b6453c94da602e8a777d1b634f61b3b4)

**Challenge 3: 🎲 Dice Game**

[https://devilish-sofa.surge.sh/](https://devilish-sofa.surge.sh/)

[https://goerli.etherscan.io/address/0x99019Dac70C60Ac8c8f2F37Fd70D6A6538737DD8](https://goerli.etherscan.io/address/0x99019Dac70C60Ac8c8f2F37Fd70D6A6538737DD8)

**Questions & Feedback:**

My experience with this week involved less spent time on coding and way more hours on trying to understand the underlying concepts. I did end up doing multiple rejected submission this week, and had to handle a lot more edge cases to get my submissions passed.

Overall, this week did bring about a steeper learning curve as compared to week 1, which was something which I was certainly looking forward to.

I’m even more hyped about week 3 now, WAGMI.

![](https://storage.googleapis.com/papyrus_images/ac5be7d53285dffa559f038a7ee6d8562772c0191a18d11cee16c8d309c67ae8.png)

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*Originally published on [Yajas Sardana](https://paragraph.com/@yajas-sardana/climbing-higher)*