Thread: not an lvalue

k obviously i am a noob, but i have observed the basic courtasies for posting. i searched for it in posts and did not find an answer, anyways...

im trying to write a code to output (part of) the fib sequence, but i keep running into the same problem.

Code:

#include <iostream.h>
int fib1[50]; 
int a=0;  
int b=1;
int c=2;
int main()
{
 fib1[a]=1; //sets fib1[whatever # a is] to start out at 1
 fib1[b]=1;
 fib1[c]=2;
 for(int x=0;x<50;x++) //set for 50 repetitions
 {
  fib1[a]+fib1[b]=fib1[c];   //value in fib1[a]+value in fib1[b]=value in fib1[b]. but for somereason my compiler is saying its not an lvalue
  a++; //increments a
  b++;
  c++;
  cout<<fib1[a]<<", ";   //outputs #s
 }
return 0;
}

i have tried putting the values from the array into int variables, but i had the same problem. same thing happended when i used pointers.

The value on the left side of the = sign, is the "unknown".

x = 5; // This is OK
5 = X; // This is NOT OK

fib1[c] = fib1[a] + fib1[b]; // Try This

In C++ (and in programming in general), the equal-sign does not indicate an equation. It is the assignment operator. It assigns the value of the statement on the right to the variable on the left.

>> fib1[a]+fib1[b]=fib1[c];

you have to put the thing being assigned on the left (lvalue)

fib1[c] = fib1[a]+fib1[b];

edit: d'oh, beaten by doug

ahhh, i see, i should have know that. thanks so much for the help