👉 The `struct fumes` in C is a predefined structure used to represent fume (or vapor) data, typically representing the concentration of toxic gases in a given volume of air. This structure includes fields such as `type`, which specifies the type of fume (e.g., hydrogen sulfide, carbon monoxide), `concentration`, indicating the partial pressure or mass fraction of the fume, and `units`, defining the units of measurement (e.g., ppm, mg/m³). It also contains pointers to dynamically allocated memory for storing the actual values of these fields, allowing for flexible and efficient handling of varying amounts of data. This structure is crucial in simulations and safety analyses where precise monitoring of hazardous gas levels is necessary.