sscanf(&A[i], "%2hhx", &B[i/2]）;这句如何理解

)The sscanf() function is a C library function that reads formatted input from a string. It works similar to the scanf() function, but instead of reading from standard input it reads from a string. The function takes two arguments: the first argument is the input string to be read, and the second argument is a format string that specifies how to interpret the input. The function returns the number of input items successfully read and assigned.

Here is the syntax for the sscanf() function:

int sscanf(const char *str, const char *format, ...);

The first argument is a pointer to the input string, the second argument is a pointer to the format string, and any additional arguments after that are pointers to variables that will receive the input values. The format string specifies how the input string should be parsed, and includes formatting codes for different types of input, such as integers, floating-point numbers, and strings.

Here is an example usage of the sscanf() function:

char input_string[] = "John 25 3.14";
char name[20];
int age;
float pi;

sscanf(input_string, "%s %d %f", name, &age, &pi);

printf("Name: %s\n", name);
printf("Age: %d\n", age);
printf("Pi: %f\n", pi);

In this example, the input_string contains the values "John 25 3.14". The sscanf() function is used to parse this input string and assign the values to the variables name, age, and pi. The format string "%s %d %f" specifies that the input string should be read as a string, an integer, and a floating-point number, respectively. The output of this program will be:

Name: John
Age: 25
Pi: 3.140000