Assign array field within struct

user_2172637 0
Viewed 73

recently i started working on C++ code and i was trying to communicate with an external library which has a struct defined as follows

struct StudentsInformation {
    int student_count[10];
    double total_marks[10];
    double section_marks_average;
    double class_marks_average;
};

I was trying to create a object for this struct as follows in a separate class

int count[10] = {1, 2, 3, 4, 5, 1, 2, 3, 4, 5}; 
double marks[10] = {10.0, 20.0, 30.0, 40.0, 50.0, 10.0, 20.0, 30.0, 40.0, 50.0};

StudentsInformation stuInfo = { count, marks, 68.8, 56.7 };

Compiling this provides following error

Cannot initialize an array element of type 'int' with an lvalue of type 'int [10]'

not sure what i'm doing wrong.

struct arrays c++
1 Answers

This should compile fine, in either/both C and/or C++:

#include <stdio.h>

struct StudentsInformation {
    int student_count[10];
    double total_marks[10];
    double section_marks_average;
    double class_marks_average;
};

int main(int argc, char *argv[]) {
  struct StudentsInformation si = {
    {1, 2, 3, 4, 5, 1, 2, 3, 4, 5},
    {10.0, 20.0, 30.0, 40.0, 50.0, 10.0, 20.0, 30.0, 40.0, 50.0},
    68.8, 56.7
  };

  return 0;
}

The key part of the error message is "cannot convert an lvalue":

https://en.cppreference.com/w/cpp/language/value_category

lvalue:

the name of a variable, a function, a template parameter object (since C++20), or a data member, regardless of type, such as std::cin or std::endl. Even if the variable's type is rvalue reference, the expression consisting of its name is an lvalue expression;

user_4211950
Related