using remove method of std::list in a loop is creating segmentation fault

I am using remove() of std::list to remove elements in a for loop. But it is creating segmentation fault. I am not using iterators. Program is given below.

#include <iostream>
#include <list>

using namespace std;

int main() {
    list <int> li = {1, 2, 3, 4, 5};
    
    for(auto x : li)
    {
        if (x == 4) {
            li.remove(x);
        }
    }

    return 0;
}

In case of iterators, I understand that iterators are invalidated if we remove an element and we need to take care of incrementing iterator properly. But here I am not using iterators and I am using remove() which doesn’t return any. Can any one please let me know if we can’t use remove in a loop or if there is any issue with the code.

>Solution :

But here I am not using iterators and I am using remove() which
doesn’t return any. Can any one please let me know if we can’t use
remove in a loop or if there is any issue with the code.

You are mistaken. Range based for loops are based on iterators. So after this call

li.remove(x);

the current used iterator becomes invalid.

For example in C++ 17 the range-based for loop is defined the following way (9.5.4 The range-based for statement)

1 The range-based for statement

for ( for-range-declaration : for-range-initializer ) statement

is equivalent to

{
    auto &&__range = for-range-initializer ;
    auto __begin = begin-expr ;
    auto __end = end-expr ;
    for ( ; __begin != __end; ++__begin ) {
        for-range-declaration = *__begin;
        statement
    }
}

Pay attention to that using the rangge-based for loop to call the member function remove does not make a great sense because the function will remove all elements with the given value.

If the compiler supports C++ 20 then you can just write

std::erase( li, 4 );