lvalue required as left operand of assignment in ios

Question

Here is my code

[[X objectAtIndex:i] doubleValue] = ([[X objectAtIndex:i-1]doubleValue] * [[X objectAtIndex:1]doubleValue]);

Where X is array of double

Thanks

Answer 1

For setting value you have to use set method, something like this:

double d = [[X objectAtIndex:i-1] doubleValue] * [[X objectAtIndex:1] doubleValue];
[[X objectAtIndex:i] setDoubleValue:d];