An essential component of a programmer’s journey are error messages. They are useful markers for when something in the programming goes wrong. Nevertheless, even beginners and experienced developers may find them confusing and annoying. It is essential to comprehend these signals and know how to respond to them in order to effectively solve programming problems. In this article, we’ll look at a few typical programming error messages and practical solutions.

Some common Types of Errors in Programming are listed below.

• Syntax Error
• Run-Time Error
• Semantic Error
• Linker Error
• Logical Error
  

1. SYNTAX ERROR:

Error Message: “SyntaxError: invalid syntax”.
An error in the syntax of a string of letters, or tokens, meant to be written in a certain computer language, is known as a syntax error. Syntax mistakes in compiled languages are found during compilation. Programming cannot begin until all syntactic faults are fixed. It can be caused by Incorrect indentation, missing parenthesis, or semicolons in the code are examples of faulty syntax.

Example of Syntax Error
Here is an example code having a syntax error:

javascript

// Syntax Error Example
let greeting = "Hello"
console.log(greeting)  // Missing semicolon at the end of the line

SOLUTION: Go over the code carefully to make sure there are no mistakes, missing symbols, or improper formatting. Syntax problems are frequently highlighted by code editors, making it easier to find and fix them quickly.

2. RUN TIME ERROR

A run-time error is a type of error that arises when a program is being executed; it can also occur when a program tries to perform an illegal operation (e.g., dividing by zero or trying to access an invalid memory address). Run-time errors are typically hard to find because they don’t manifest themselves until the program is actually executed

Example of Run time Error
Here is an example code having a Run time error:

Javascipt

// Runtime Error Example
let number = 10;
let text = "Hello";
let result = number.toUpperCase();  // Attempting to use a string method on a number
console.log(result);

SOLUTION : In order to fix a runtime mistake, one must carefully examine the code, comprehend how it is executed, and make the required changes to guarantee that variables are managed correctly and operations are carried out on the right kinds of data throughout the program’s runtime.

3. SEMANTIC ERROR

When a programmer writes code that is syntactically valid but fails to make sense to the compiler, this is known as a semantic error. Semantic error relates to the meaning and execution of the program, in contrary to syntax errors, which refer to faults in the program’s structure.

For example:

• Using a string instead of an integer or accessing an array index that is out of bounds can cause semantic errors.
• Uninitialized variables and type incompatibility are other common types of semantic errors.

Example of Semantic Error
Here is the code for a better understanding of Semantic Errors in HTML.

In this case, the <span> element is used to represent an important heading within a <div> element styled as a header. However, semantically, using a <span> for a heading isn’t the best practice. A more appropriate tag for a heading would be <h1> to <h6>, depending on the importance and hierarchy of the heading:

Explanation:

• Semantic Error: The initial code uses a <span> element for an important heading, which doesn’t semantically represent a header in HTML. Semantic HTML elements like <h1> to <h6> should be used for headings, as they convey the structure and importance of content.
• Semantic Error Corrected: The corrected code replaces the <span> with an <h1> element, which better represents an important heading within a header section. This modification ensures that the content’s meaning is conveyed correctly and aligns with HTML’s semantic structure.

4. LINKER ERROR

When a program is being compiled, linking problems might arise. These errors occur when problems like as missing functions or symbols are encountered by the linker, which is in charge of fusing many object files and libraries into a single executable.

c++

#include <iostream>
using namespace std;
int main() 
{
  cout << "Hello, world!" << endl;
  myFunction();
  return 0;
}

Output

prog.cpp: In function ‘int main()’:
prog.cpp:7:3: error: ‘myFunction’ was not declared in this scope
   myFunction();
   ^~~~~~~~~~

Explanation:
Although the function called myFunction() is called in the code above, neither the program nor any of its libraries declare it. The linker displays the error “myFunction() is undefined” on the output screen as soon as the program is compiled.

5. LOGICAL ERROR:

When a program runs and compiles without any syntax, run-time, or linker issues but produces an inaccurate result, it is a logical mistake. When the logic or algorithms used by the software are flawed, these problems happen. The lack of error signals generated by the application makes it difficult to identify logical faults.

Javascript

// Example of a Logical Error
function calculateAverage(numbers) {
    let sum = 0;
    
    // Calculate sum of numbers
    for (let i = 0; i <= numbers.length; i++) { // Incorrect loop condition (should be i < numbers.length)
        sum += numbers[i];
    }
    
    // Calculate average
    let average = sum / numbers.length;
    return average;
}
// Test the function
let numbers = [10, 20, 30, 40, 50];
let result = calculateAverage(numbers);
console.log("Average:", result);

Expected Output:

The code will not throw an error, but it will produce an incorrect average due to the logical error in the loop condition. It will likely result in NaN (Not a Number) being returned as the average.

SOLUTION:

To correct this logical error, you should adjust the loop condition to i < numbers.length to ensure that the loop iterates through all the valid indices of the numbers array without going beyond its length:

// Corrected loop condition
for (let i = 0; i < numbers.length; i++) {
    sum += numbers[i];
}

This adjustment ensures that the loop iterates from 0 to numbers.length - 1, allowing the correct calculation of the sum of numbers and subsequently the accurate average.

In summary
To sum up, programming is a challenging endeavor that necessitates a keen eye for detail. Programming mistakes can happen at several phases of the process. Programming faults can be of many various kinds, such as syntactic, logical, semantic, run-time, and linker problems. Run-time problems are frequently the hardest to find, although syntax errors are the most prevalent kind. While logical and semantic mistakes arise from misinterpreting the program’s requirements or procedures, linker errors happen during the compilation and linking process.