Code conversions to monkey C

Hello again, 

I'm taking my second attempt at converting someone else's code below ( Not Monkey C ), into an equivalent code line. Can someone please take a quick look, I don't know if the right thing to use is an Array or dictionary, or use classes and functions?

SOURCE CODE

typedef union {
    float array[3];

    struct {
        float x;
        float y;
        float z;
    } axis;
} FusionVector3;

static inline __attribute__((always_inline)) FusionVector3 FusionVectorAdd(const FusionVector3 vectorA, const FusionVector3 vectorB) {
    FusionVector3 result;
    result.axis.x = vectorA.axis.x + vectorB.axis.x;
    result.axis.y = vectorA.axis.y + vectorB.axis.y;
    result.axis.z = vectorA.axis.z + vectorB.axis.z;
    return result;
}
------------------INTO-------------------------
var FusionVector3 = new[3];

FusionVectorAdd(vectorA, vectorB){
    FusionVector3[0] = vectorA[0] + vectorB[0] ;
    FusionVector3[1] = vectorA[1] + vectorB[1] ;
    FusionVector3[2] = vectorA[2] + vectorB[2] ;
    }