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What Is Code Quality?

Code quality — producing software free of critical defects that meets its functional and nonfunctional requirements — should always be among a project’s primary goals. But other metrics affect code quality like adopting processes in the software development lifecycle that ensure the production of high-quality code.

What Is Code Quality?

Determining code quality can be subjective and open to argument. After all, there are various purposes and degrees of criticality that code serves.

High quality code and lines of code on a distorted computer screen.


Code that checks your spelling while writing a document is not very critical compared to code that runs your implantable cardioverter-defibrillator in treatment for sudden cardiac death due to ventricular tachyarrhythmias. Yet, most will be consistent with the contention that error-free code which reliably performs its intended function defines code quality. The maintainability of functionality is critical regardless.

However, there are other properties to code that contribute to high-quality code that should not be omitted from this equation. These include code maintainability, clarity, testability, portability, robustness, reusability, complexity, safety, security, and more.

These code quality metrics can determine how a single piece of code might affect the overall quality of your code. Code review tools offer one more vector toward avoiding low-quality code, time-consuming fixes, and the other common pitfalls developer teams face during software development. Knowing what makes quality code is just as important as knowing how to measure code quality.

Benefits of Code Quality

Implementing technical and cultural measures in delivering high-quality code has everlasting benefits. They all impact product success, software quality, and longevity including labor costs and time to market. Streamline the development process, up your quality standards, and improve code analysis to further enhance future projects.

Product Confidence & Reputation

High-quality code (safe, secure, reliable, and so on) will perform to or exceed your customers' expectations. Not only will it instill trust and confidence that your organization runs a sound business, but that you deliver quality products and it’s not worth the risk of going elsewhere.

Promotes Reuse

Code that is safe, secure, reliable, and of quality should be considered for reuse, especially if it was written with portability in mind. This will cut your development and testing costs dramatically in future products.

Diminishes Technical Debt

Implementing code quality procedures like code reviews, static analysis, unit testing, code coverage, and more will reduce the amount of rework and costs (technical debt). This would have to be paid if these methods were deemphasized or omitted from the software development lifecycle. The highest costs to technical debt will be incurred once the product is out in the field, so a careful balance between code quality and delivery of speed needs to be considered.

Increases Product Longevity

Good code that's not just well architected but also well implemented can be easily and quickly enhanced with new capabilities or new features. This gives longevity and opportunities for ongoing revenue gains — no matter what algorithm changes or technology updates might occur. Code quality also contributes to the ease of maintainability and low labor costs if software issues do arise.

Parasoft Test Automation Tool Suite

Parasoft offers a suite of software test automation tools for use in the development and delivery of high-code quality compliant to industry functional standards. It automates tedious manual work, reducing labor costs associated with software verification and validation. Various tools address specific needs from static code analysis tools to security issues, quality control, and beyond.

Code Quality Best Practices

When it comes to quality coding, there are several highly beneficial practices. Every team has its own secret sauce to prevent bad code or, as some programmers might say the code “smells”. While some in-house rules are fine to have, relying on a fixed set of practices provides more stability in the long term. Here's a list of some of the methods to consider. Also, take into account the balance between software criticality and speed of delivery.

Code/Peer Reviews

Convene with your fellow software engineers and systematically check each other's code for mistakes and coding style violations. This activity has been shown to accelerate and substantially improve code quality.

Code Robustness

Write code to handle not just the sunny day scenarios, but rainy days too. Also, perform negative testing, which is to apply as much creativity as possible when validating the application against invalid data.

Use or Write Code That's Safe

For safety-critical applications, make sure to apply a static analysis solution like MISRA, AUTOSAR, or other coding standards that will identify the use of coding constructs that are unsafe (divide by zero, use of a NULL pointer and so) and can cause a dreadful condition.

Use or Write Code That's Secure

For applications that need to be secure, make sure to apply a static analysis solution like CERT, OWASP, or other coding standards that will identify insecure and vulnerable conditions (buffer overflows, information leakage, script injection, and so on) for an attack.

Code Clarity

Write code that's easy to read and understand. Don’t be too clever and write cryptic code that's hard to follow or easily misunderstood. You don't want other engineers or yourself to spend a lot of time trying to decipher a bug in your code. Rooting out an odd indentation, niche formatting, or errant lines of code takes time. All of that refactoring adds inefficiency and cost to projects, which affects the maintainable quality of code.

Code Complexity

Write code that doesn't have a large number of branches. The more branches, the higher the code complexity and the higher number of bugs found in the code. Reduce branches by building functions to break up the complexity. However, remember that complexity measures and complexity metrics play roles in the maintainability, reliability, and readability of your codebase. It also simplifies pull requests. For more information about these software metrics, consider Halstead complexity measures in order to measure complexity from the source code.

Code Portability

Write code with portability in mind. Portable code, such as POSIX, ANSI C, and more, can be easily and quickly moved to other platforms either to use with other compilers or other operating systems and can be done with minimal changes to facilitate the migration. Many times, there are financial opportunities or reasons why running on another operating system or target needs to happen.

Code Reusability

Write code with well-defined interfaces so that it can be reused in future products or projects. This improves productivity in the workflow and reduces labor and testing costs. Many open source projects found on sites like Github offer great examples of code clarity and reusability given the nature of the projects.

Example of Code Quality

Parasoft uses automation to ensure code quality within your favorite IDE or CI/CD pipeline and provides a reporting and analytics dashboard.

Screen capture of Parasoft C/C++test and DTP Report Center showing MISRA C 2012 Compliance

How to Get Started With Code Quality

Step 1: Code Review by Peers

If you’re experiencing poor code quality issues (bugs, regressions, high maintenance costs, and so on), the first remedy to apply is code peer reviews.

Having a group of engineers visually and collaboratively step through the code that each engineer has written is one of the most important code quality activities that an organization can perform. Different minds with various levels of experience, coding styles, and logic thought can quickly expose issues in the code that can be remedied before they are committed into the development stream.

Young black developer ensuring code quality and functionality in the development process.

Step 2: Static Analysis

The second most important step is performing static analysis on the code, using industry coding standards such as MISRA, AUTOSAR, CERT, CWE, OWASP, UL 2900, or others. These standards have been developed and designed by software engineers with decades of experience in writing safe, secure, and reliable software.

Parasoft can automate your static analysis by finding and reporting any code rule or directive violation during the implementation phase and you can also choose to automate the analyzer as part of your build process or continuous integration pipeline.

Step 3: Code Testing

The third step is to test the code at the various verification phases of the software development lifecycle (SDLC). Unit, integration, system, and acceptance testing. Create test cases for each SDLC phase and ensure that requirements are satisfied and that the functionality or code is robust, in that it can handle your sunny, rainy, and negative execution scenarios.

If your quality issues are security, safety, portability, or another specific topic, focus on solving these issues during implementation when they are the least expensive to resolve or focus your quality assurance efforts in these specific areas. For example, if security is the issue, then incorporate or improve the testing techniques (risk assessment, penetration testing, API security testing, security scanning, and more) needed to find security vulnerabilities.

Why Parasoft?

Parasoft is unique in that it offers automated and continuous testing solutions for enterprise software development and end-to-end testing solutions for embedded safety- and security-critical systems. In addition, Parasoft offers software security solutions that protect against vulnerabilities.

Businesses need to accelerate delivery to meet customers’ needs. Parasoft’s Continuous Quality Suite ensures your software is reliable, scalable, and secure to deliver a win in high-stakes enterprise software development.

Embedded software requires thorough testing at each phase of the software development life cycle, from system and high-level design to unit and integration testing.

Parasoft covers all your needs with dedicated, automated tools and solutions for each step in both the verification and validation stages. You can achieve compliance to industry process standards and deliver quality software.

Given the frequency of cyberattacks, your code cannot afford security vulnerabilities. Nor can you afford to make security an afterthought. Embed security standards into your software development from the start.

Conduct static application security testing (SAST) with Parasoft AI-powered security tools (supporting more than 25 languages and frameworks) and leverage API security testing to verify your functional security requirements. We offer blogs, recorded webinars, whitepapers, and more to assist team members.

Frequently Asked Questions

Code quality tools are software development and testing solutions that automate the process of identifying code defects. These tools can be applied within the various phases of your software development.

There are all kinds of code quality analyses to capture requirements like achieving 100% structural code coverage to tools that instrument the code and validate that 100% of the code has been exercised by way of testing.

There are also tools that automate unit tests, integration, and system testing. Based on your application and if there are any safety-/security-critical needs, there are software testing tools to help flush out security vulnerabilities, like penetration testing, and safety issues, as well. Security analysis should never go overlooked.

Code quality metrics are a number of variables used to measure and determine if code is of high quality. Teams can then use those metrics for code review for changes, test coverage, and other actionable insights.

Variables such as code complexity, portability, security, clarity, reusability, and others. Code complexity for example is commonly measured using McCabe’s cyclomatic complexity approach.

A tally of the number of linearly independent paths along with a number of conditional or decision points is used to determine the complexity. A control flow graph is used to visually capture nodes, edges, and paths. The mathematical formula is M=E-N+2P. M is complexity, E is the number of edges, N is the number of notes and P is the number of connected components.

Coding acts as programming languages that humans can learn to read and write. The code provides instructions to the device or computer system on what to do or functionality to perform. There are various coding languages like C, C++, Java, C#, VB.NET, Python, JavaScript, Fortran, Ada, and many more. These coding languages ultimately get translated to binary code which is the language that computers/processors can understand. Code is the building block that defines software applications. Applications, like Microsoft Word, Angry Birds, and Boeing’s 777 autopilot mode.