無效操作數的二進制表達（「雙」和「雙」）目標c問題

Question

無效的操作數的二進制表達（「雙」和「雙」）目標c問題

-(double)performOperationWith:(double *)operand1 
         And:(double *)operand2 { 

    double result = 0.0; 

    result = operand1 + operand2; 

    return result; 
} 

Answer 1

他們三分球，所以你應該取消引用它們：

result = *operand1 + *operand2; 

或者更改功能參數：

-(double)performOperationWith:(double)operand1 And:(double)operand2 {...} 

Answer 2

只需卸下* ：

-(double)performOperationWith:(double)operand1 And:(double)operand2 { 
    double result = 0.0; 
    result = operand1 + operand2; 
    return result; 
}