# Week III
## Debug
- Tracing the flow of a program

def main():
    total = 0
    for i in range(100):
        new_total = total + i
    print(f"The sum of the first 100 numbers is {new_total}")

- `str(new_total)` -->

## Frontends vs Backends

- Logic <--> Backends
- Interaction <--> Frontends

## Decomposing Running Sum
### Interact with the user
- Function to loop the program
- Conditional to handle the exit
### Calculate
- Handle each input
- Track previous inputs

> Premature optimization is never good **Yak Shaving** -- Common
> Good design is *not* premature optimization -- Rohit