Expression processing

[vorticidal]

I've been trying to understand how C++ works through expressions, and built a small program to play with them.

#include"stdio.h"
#include"stdlib.h"

class Object{
	public:
	
	int value;
	
	Object(){value=0;}
	Object(int a){value=a;}
	
	Object operator+(Object);
};

Object Object::operator+(Object rhs){
	printf("i have value %d, it has value %d\n",value,rhs.value);
	return Object(value+rhs.value);
}

int main(){
	
	Object o1(1);
	Object o2(2);
	Object o3(4);
	Object o4(8);
	Object o5(16);

	o1+(o2+o3)+(o4+o5);
	
	return 0;
}

When I run this code, the program outputs

i have value 8, it has value 16
i have value 2, it has value 4
i have value 1, it has value 6
i have value 7, it has value 24

How come it didn't output

i have value 2, it has value 4
i have value 1, it has value 6
i have value 8, it has value 16
i have value 7, it has value 24

instead?

I'm using GCC to compile.

[mzimmers]

The compiler resolves multiple term expressions according to the heirarchy of the operators. In this case, the parens are higher precedence than the addition. The only thing I don't understand are why the first two lines aren't swapped, since I'd have figured it would do the first parens first, as they associate left to right.

[vorticidal]

That's what I'm saying.