It is estimated that a lot of students are c++/java/c# these three popular language operation mechanism and execution efficiency has more or less confusion, oneself also has, but after the previous study, understood three in these two aspects difference, on nonsense not to say, enter the subject bar.
Operation Mechanism 1, java-compiled and interpreted language a Java file, first compiled by the Java Compiler (JAVAC) into a class (bytecode file) file, and then by the Java Virtual Machine (JVM) to explain. Different operating systems can be interpreted and run as long as the Jdk,java files are installed for different platforms. Java is a compile-and-interpret language.
The main reason that the bytecode file (class) can be interpreted by the Java Virtual Machine (JVM) is that the content contained in the bytecode file (class) is a highly optimized instruction that can be interpreted by the Java Virtual Machine (JVM).
Java files need to be compiled once to explain the operation on different operating systems, that is to say, one compilation runs everywhere, which is why Java can cross the platform. 2, c++-compiled language C + + does not have the concept of virtual machines, which means C + + Once compiled, it is a compiled language that is much faster than Java, and after C + + is compiled, the machine code (binaries) can be run directly on the operating system. 3, c#-compiled and re-compiled language C # with the same, there are virtual machines, But his virtual machine is the CLR (the common language runtime). A C # file, first compiled by the C # compiler into a low-level intermediate-language IL, is then compiled into machine code by the C # virtual machine, which is the common language runtime (CLR), which is then executed by the Cup. So C # execution has to be compiled two times. implementation Efficiency 1, speed of Operation In this respect, C + + is the fastest. Because C + + compiled into machine code can be run directly, but Java compiled after the JVM needs to explain, C # compiled by the CLR will need to be compiled two times. 2, compiling efficiency from this aspect, C + + compiled machine code is not common to every operating system, if you switch to other operating systems need to compile again. Similarly, C # passes two compiled machine code. So this time the Java JVM Advantage is reflected, Java bytecode files run everywhere, another operating system still do not need to compile again. So, from the compilation efficiency, Java is the highest. 3, security considerations from a security perspective, C # is the most secure of these languages, and it defines the relevant security mechanisms to ensure the security of the system well. &nbsP; Personal summary: younger brother summarized as follows: C + + does not guarantee a certain efficiency higher than Java and C #, just like assembly language does not guarantee high efficiency over C. But they all provide a more efficient opportunity, first of all you have to be high enough to write more efficient programs, otherwise, even if you use C++/C or even assembly, it is possible to generate a low-efficiency program. Second, for C + + also depends on the compiler you use to write the level of high and low, see you compile with what kind of optimization. In other words, what language is used for development is far from being a factor of high execution efficiency, and in most cases, execution efficiency is a non-critical factor in the very back line.
Talking about c++/java/c# operation mechanism and execution efficiency
