C/C++. input line of numbers - c++

Question

Need to input data about multiple structure variables (format - 3 groups of 2 numbers in one line). Used "for" and custom input function (also it calculates some parameters). Now tryed to use "std::cin" :
typedef struct {
short width;
short height;
short left;
short top;
int S;
short orientation;
} Rectangle;
bool input_rectangle(Rectangle* rect) {
short width;
short height;
std::cin >> width >> height;
(*rect).width = width;
(*rect).height = height;
(*rect).S = width * height;
(*rect).top = 0;
(*rect).left = 0;
if(width>height) {
(*rect).orientation = HORIZONTAL;
}
else {
(*rect).orientation = VERTICAL;
}
return width!=0 || height!=0;
}
int main() {
Rectangle* rectangles = new Rectangle[RECTANGLES_COUNT];
...
while(1) {
...
for(int i=0;i<RECTANGLES_COUNT;i++) {
will_continue = will_continue || input_rectangle(&rectangles[i]);
}
if(!will_continue) {
break;
}
else {
int S = calculate(rectangles);
}
...
}
}
It give wrong result. Tryed to add debug output to "calculate" :
for(int i=0;i<RECTANGLES_COUNT;i++)
std::cout << rectangles[i].width << " x " << rectangles[i].height << " = " << rectangles[i].S << "\n";
Example of result.
4 16 6 6 5 10 #my input
4 x 16 = 64 #right
0 x 0 = 0 #??? Must be 6 x 6 = 36
0 x 0 = 0
646 x 6 = 36
0 x 0 = 0
0 x 0 = 0
365 x 10 = 50
0 x 0 = 0
0 x 0 = 0
How can I improve it? Also I tryed to use scanf("%hd %hd", &width, &height); (may ise pure C in this task), but it give same result.
Used g++ compiler / (gcc for pure C version)

Answer 1

From your debug output code, I'm gathering that for your test purposes RECTANGLES_COUNT is actually defined to 3.
Also, since it is able to perform any kind of computations, and given that the || operator is subject to lazy-evaluation, you must be initializing will_continue to false.
What's happening is when your first input (i=0) is in fact valid (i.e. width or height is not 0), will_continue gets set true. Then since true || anything must be true, input_rectangle is no longer called (lazy-evaluation) for i=1,2,... So only rectangle[0] gets set in that loop. When you latter call your debug output in calculate, you show all 3 rectangles' width/height/S including 2 that have presumably been initialized to 0 (and remain to their initial value).
I'm guessing (though not shown) that int S = calculate(rectangles) might in fact assigns the sum of rectangle[i].S (which happens to be equal to rectangle[0].S, since the others are 0s) to S which you are then printing. That would explain the lines containing 646 (64 followed by 6 x 6) and 365 (36 followed by 5 x 5).
I'm guessing what you wanted was probably more along the lines of:
...
while(1) {
...
bool will_continue = false;
for(int i=0;i<RECTANGLES_COUNT;i++) {
will_continue = input_rectangle(&rectangles[i]);
if (!will_continue) {
break;
}
}
if(!will_continue) {
break;
}
else {
int S = calculate(rectangles);
}
...
}

Answer 2

return width!=0 || height!=0;
should be
return width!=0 && height!=0;