Ce tip de date este cel mai optim pentru stocarea și lucrul cu valori monetare?

Zecimal.

Are high precision, allowing storage of up to 28-29 significant digits and intended for financial calculations where accuracy is critical. Unlike float and double, which use binary representation and can lead to rounding errors when working with decimal numbers, decimal uses a decimal representation, which eliminates such problems.

Example of usage:

// Declare a decimal variable to store monetary value
decimal price = 19.99m;

// Perform arithmetic operations with monetary values
decimal taxRate = 0.20m;
decimal total = price * (1 + taxRate);

// Display the exact result
Console.WriteLine($"Total price: {total}"); // Output: Total price: 23,988

Comparison with other data types:

Data type	Approximate range of values	Precision	Suitable for monetary values?
float	±1.5 x 10⁻⁴⁵ to ±3.4 x 10³⁸	7 decimal digits	No
double	±5.0 x 10⁻³²⁴ to ±1.7 x 10³⁰⁸	15-17 decimal digits	No
decimal	±1.0 x 10⁻²⁸ to ±7.9228 x 10²⁸	28-29 decimal digits	Yes

Utilizarea decimal asigură precizia și fiabilitatea necesare în lucrul cu date financiare, prevenind erorile de rotunjire care pot apărea la utilizarea tipurilor cu virgulă mobilă.