Where is the starting point of C language program?

What is the starting point for running a C language program?

C language, as a high-level programming language, is one of the most commonly used programming languages. In the process of learning C language, many people will be confused about the starting point of running C program. So, what is the starting point for running a C language program?

The answer is main function. In C language programs, the execution of the program starts from the beginning of the main function. The main function is the entry point of the C language program and the first function defined by the programmer to be executed. Its main function is to define the execution logic of the program and call other functions.

The prototype of the main function is usually:

int main() {

// 代码逻辑
return 0;

}

In the main function, the specific implementation of the code logic is based on the program vary according to needs. You can define variables, call other functions, perform various operations, etc. in the main function. At the end of the function, an integer value is returned through the return statement. Generally, returning 0 indicates that the program has ended normally, and returning other values ​​indicates that an exception has occurred in the program.

When a program starts running, the operating system starts the program by calling the main function. It will execute line by line according to the code logic in the main function until it encounters the return statement. Before executing the return statement, various functions can be implemented by calling other functions.

In addition to the main function in the above form, C language also supports the main function with command line parameters. The prototype of the main function with command line parameters is usually:

int main(int argc, char *argv[]) {

// 代码逻辑
return 0;

}

where argc represents the command The number of line parameters. argv is a string array that stores the specific values ​​of the command line parameters. By entering parameters on the command line, you can change the execution logic of the program and increase the flexibility of the program.

In summary, the starting point for running a C language program is the main function. The program starts execution from the beginning of the main function and executes it line by line according to the code logic until it encounters the return statement. Various functions can be implemented by defining and calling other functions. Understanding the starting point of running a C language program is very important for learning and mastering C language programming.

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