error C2106: '=' : left operand must be l-value c++

Question

I'm getting a C2106: '=' : left operand must be l-value error on the line with *shp[count]).area()=max; and I'm not sure what that means. The shape class is a base class for all of the shapes and I'm trying to put them all in an array of type shape and find which one has the largest area

int largestArea()
{
float max =-99999;
int index = 0;
shape *shp[6];
shp[0 ]= new trapezoid (4,6,3);
shp[1 ]= new triangle  (4,2);
shp[2 ]= new parallelogram (3,8);
shp[3 ]= new trapezoid (2,6,3);
shp[4 ]= new triangle  (5,2);
shp[5 ]= new parallelogram (2,7);

for(int count=0;count<6;count++)
{
    if((*shp[count]).area()>=max)
    {
        (*shp[count]).area()=max;
        index = count;
    }
}

return index;

That error says that you're trying to assign to something that is not assignable. — Adam, Nov 11 '13 at 06:12
possible duplicate of [error C2106: '=' : left operand must be l-value](http://stackoverflow.com/questions/17930948/error-c2106-left-operand-must-be-l-value) — Raymond Chen, Nov 11 '13 at 06:13
So, what is your intent with that `(*shp[count]).area()=max` assignment? What are you trying to do by this? — AnT stands with Russia, Nov 11 '13 at 06:14
@AndreyT im trying to get the value of the area in the array and make it that max but only if its larger then it — DaCat, Nov 11 '13 at 06:17
Well, if you want to update the current `max`, then it should be `max = (*shp[count]).area()`. Why did you do it the other way around? — AnT stands with Russia, Nov 11 '13 at 06:18
@AndreyT just my mistake i haven't been programming too long — DaCat, Nov 11 '13 at 06:21

score 4 · Accepted Answer · answered Nov 11 '13 at 06:12

4

You meant to assign max. Try this:

max = (*shp[count]).area();

answered Nov 11 '13 at 06:12

Phillip Kinkade

1,382
12
18

haha wow im an idiot this is the second time i did this i think this may be the problem..... thanks a lot that was the problem – DaCat Nov 11 '13 at 06:18

score 2 · Answer 2 · answered Nov 11 '13 at 06:26

2

I know I'm slightly off-topic.

Why don't you write this?

size_t index = 0; 
float max = (*shp[0]).area(); 

for(int count=1;count<6;count++)
{
    if((*shp[count]).area()>=max)
    {
        max = (*shp[count]).area();
        index = count;
    }
}

Reading things like:

float max =-99999;

is unpleasant.

answered Nov 11 '13 at 06:26

jimifiki

5,377
2
34
60

Thanks for the tip will consider next time – DaCat Nov 11 '13 at 18:31

error C2106: '=' : left operand must be l-value c++

2 Answers2