Memory faults are major forms of software bugs that severely threaten system availability and security in c/c++ program. Many tools and techniques are available to check memory faults, but few provide systematic full-scale research and quantitative analysis. Furthermore, most of them produce high noise ratio of warning messages that require many human hours to review and eliminate false-positive alarms. And thus, they cannot locate the root causes of memory faults precisely. This paper provides an innovative state machine to check memory faults, which has three main contributions. Firstly, five concise formulas describing memory faults are given to make the mechanism of the state machine simple and flexible. Secondly, the state machine has the ability to locate the cause roots of the memory faults. Finally, a case study applying to an embedded software, which is written in 50 thousand lines of c codes, shows it can provide useful data to evaluate the reliability and quality of software.