struct数组的赋值

Question

    extern struct aStruct aStruct_table[4];
    
int main()
{
        aStruct_table[0].val1 = 0;
        aStruct_table[0].val2 = 0x0;
        aStruct_table[0].val3 = 0x130;
        aStruct_table[1].val1 = 1;
        aStruct_table[1].val2 = 0x140;
        aStruct_table[1].val3 = 0x860;
        aStruct_table[1].val1 = 4;
        aStruct_table[1].val2 = 0x2050;
        aStruct_table[1].val3 = 0x1950;
        aStruct_table[1].val1 = 7;
        aStruct_table[1].val2 = 0x6000;
        aStruct_table[1].val3 = 0x666;
}

Is there another way to assign the struct array without having so much code? Maybe sth like

    extern struct aStruct aStruct_table[4] = {{0,0x0,0x130},
                                             {1,0x140,0x860},
                                             {4,0x2050,0x1950},
                                             {7,0x6000,0x666}};

Answer 1

You are mixing up assignment and initialization, I guess.

In modern C, AKA C99, the best way to do initialization of a struct is with "designated initializers"

struct aStruct A = { .val1 = 0, .val2 = 0x0A };

and the syntax for arrays of structs is just to repeat that:

struct aStruct B[] = {
   { .val1 = 0, .val2 = 0x0A },
   { .val1 = 2, .val2 = 0x0B }
};

But you shouldn't do it with the extern in front. That one is for the forward declaration in the header file without the initialization part.

If you really meant assignment, for struct you can use "compound literals

A = (struct aStruct){ .val1 = 0, .val2 = 0x0A };

but as you probably know there is no assignment syntax for arrays.

Answer 2

Yes, it is perfectly legal to do that.

With C99 initializers it can be even clearer:

extern struct aStruct aStruct_table[4] = {
    [0] = {
        .val1 = 0,
        .val2 = 0x0,
    },
    [1] = {
// etc etc