error: called object ‘xxx‘ is not a function or function pointer

Encountered an error when compiling the code:

error: called object ‘xxx’ is not a function or function pointer|

Cause: Mathematical expression is wrong or some mathematical function is used but the header file containing it is not imported

Solution:¶

1. Check whether the mathematical expressions in the code are written incorrectly. Common mistakes are the omission of the multiplication sign'*' or the division sign'/' in the expression, which is incorrectly written as'÷', and the parentheses in the array do not match, such as: Wrongly write arry[i] as arry(i) or write arry[i][j] as arry[i,j], etc.
2. If you use library functions such as absolute value, trigonometric function, etc., check whether the header file <math.h> is added