How might I introduce an expression in a struct definition in C?-CodePudding

I defined a struct:

struct Low {
     double high;
     double low;
     double fraction;   // = (Low.high - Low.low) / Low.high; 
     double percentage; // = Low.fraction * 100;  
} low2015, low2018, low2021, low2022;

The comments hint at what I am getting at. I would like to introduce an expression in the definition block of the struct Low so that I do not have to manually do the assignment of my_struct.fraction and my_struct.percentage

low2021.high = 64854; 
low2021.low = 28805;
low2021.fraction = (low2021.high - low2021.low) / low2021.high;
low2021.percentage = low2021.fraction * 100;

for all the four variables, i.e. low2015, low2018, low2021, low2022. How might I accomplish this?

CodePudding user response：

The structure is small enough to be returned by value. Consider adding a function MakeLow().

struct Low {
     double high;
     double low;
     double fraction;
     double percentage;
};

static inline struct Low MakeLow(double high, double low) {
    return (struct Low) {
      .high = high,
      .low = low,
      .fraction = (high - low) / high,
      .percentage = (high - low) / high * 100,
    };
}

Usage:

struct Low low2021 = MakeLow(64854, 28805);