Coding⏱️ 2 min read📅 2026-05-30

How to Fix: error: passing const xxx as 'this' argument of member function discards qualifiers

Passing const reference as 'this' argument discards qualifiers. Use non-const references or pointers to fix.

Quick Answer: Replace const references with non-const references or pointers in the operator< function.

The error 'error: passing const xxx as 'this' argument of member function discards qualifiers' occurs when a non-const object is passed to a function that expects a const object. In your case, the issue lies in this line:

💡 Why You Are Getting This Error

  • [Cause]

🛠️ Step-by-Step Verified Fixes

Method 1: Using a Non-Const Pointer

  1. Step 1: Declare a non-const pointer to the StudentT object, e.g., StudentT* s1 = new StudentT(0, "Tom");

Method 2: Passing by Reference

  1. Step 1: Modify the StudentT class to take a reference to itself instead of using this, e.g., void StudentT::someFunction(StudentT& s) { ... }

✨ Wrapping Up

By applying these fixes, you can resolve the error and continue writing your code without any issues.

Did this fix your problem?

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