Returning struct from functions syntax in VC++

[Vaclav]

Could anybody point me to a basic source of information on using struct in functions - passing as parameters and returning from functions. I am confused regarding the difference in C an C++ syntax. I am looking for using arrays of struct. Thanks for your time Vaclav

[Christian Graus]

Passing arrays is the hard bit, a struct is just like a class, you can pass it in and you can pass it out. If I wanted to return an array of items, I'd probably take a std::vector by reference, and add them to that. Christian Graus - Microsoft MVP - C++

[basementman]

Structs are typically passed by pointer. In the case of struct arrays, it really depends on how you allocate the array. By incrementing a struct pointer, you actually increment the pointer to point to the next struct (the compiler increments it by the sizeof() the struct). EX:

typedef struct _MyStruct
{
int iValue;
char caData[21];
} MyStruct;

MyStruct *StructFcn(MyStruct *spStruct, int iCount);

void PassStructToFcn()
{
MyStruct *spRetval = NULL;
MyStruct sStruct;

sStruct.iValue = 7;
strcpy(sStruct.caData,"Hello");

spRetval = StructFcn(&sStruct,1);
}

void PassStructArrayToFcn()
{
MyStruct *spRetval = NULL;
MyStruct sStruct[3]; // array of 3 structs

sStruct[0].iValue = 2;
strcpy(sStruct[0].caData,"Hello");
sStruct[1].iValue = 3;
strcpy(sStruct[1].caData,"Hello");
sStruct[2].iValue = 7;
strcpy(sStruct[2].caData,"Hello");

spRetval = StructFcn(&sStruct[0],3);
}

MyStruct *StructFcn(MyStruct *spStruct, int iCount)
{
// find the struct who's value is 7
for (int iLup = 0; iLup < iCount)
{
if (spStruct->iValue == 7)
return spStruct;

  spStruct++;
}

return NULL;
}

onwards and upwards...  -- modified at 12:58 Monday 12th December, 2005