👀 Views: 4159 💬 Answers: 1 📅 Created: 2025-06-12

c floating-point structs financial-calculations C

I need some guidance on I'm trying to implement Hey everyone, I'm running into an issue that's driving me crazy... This might be a silly question, but After trying multiple solutions online, I still can't figure this out. This might be a silly question, but I'm working with unexpected behavior with floating point precision in a struct I created for handling financial transactions in C. My struct looks like this: ```c typedef struct { char description[50]; float amount; } Transaction; ``` I store several transactions and then compute the total amount. However, I noticed that when I sum up the amounts, the result is not what I expect. For instance: ```c Transaction transactions[3]; strcpy(transactions[0].description, "Payment 1"); transactions[0].amount = 100.50; strcpy(transactions[1].description, "Payment 2"); transactions[1].amount = 200.75; strcpy(transactions[2].description, "Payment 3"); transactions[2].amount = 50.25; float total = 0; for (int i = 0; i < 3; i++) { total += transactions[i].amount; } printf("Total Amount: %.2f\n", total); ``` When I run this code, I get an output of `Total Amount: 351.00`, which seems correct, but I later found out that rounding errors were occurring when displaying the amounts individually. For example, if I print out `transactions[0].amount`, it shows `100.50` but in a later calculation, `total` shows some inaccuracies when adding more transactions. I tried changing `float` to `double` for more precision but it didn't seem to fully resolve the scenario. I'm using GCC version 10.2 on Ubuntu 20.04. Is there a recommended approach to handle financial calculations in C to avoid issues with floating point precision? Should I be using a different data type or library? Any advice would be greatly appreciated! This is part of a larger web app I'm building. I'd really appreciate any guidance on this. This is part of a larger API I'm building. For reference, this is a production microservice. What's the correct way to implement this? I'm working on a service that needs to handle this. Am I approaching this the right way? This is my first time working with C 3.10. Cheers for any assistance!