不能将“double”转换为“double*”，用于参数“1”到“float sumall”(double arr[])

I am a C & Assembly programmer. But C++ is so dumb. I cannot understand what I am doing wrong here. Can someone explain to me why I am getting this error? Here is my code: GNU nano 2.2.6 Файл: assignment4.cpp I am a C & Assembly programmer. But C++ is so d