My question about the question itself of K&R C book exercise 6.2

When I was finishing exercise 6.2, this is what it says:

Exercise 6-2. Write a program that reads a C program and prints in alphabetical order each group of variable names that are identical in the first 6 characters, but different somewhere thereafter . Don't count words within strings and comments. Make 6 a parameter that can be set from the command line.

Unfortunately I was NOT able to understand something like this

prints in alphabetical order each group of variable names that are identical in the first 6 characters

Could someone explain it a bit to me? Given the c program I am about to read is the following:

int main(int argc, char *argv[]){     char line[MAXLINE];     long lineno = 0;     int c, except = 0, number = 0, found = 0;     while (--argc > 0 && (*++argv)[0] == '-'){         while (c = *++argv[0]){             switch(c){                 case 'x':                    except = 1;                    break;                 case 'n':                    number = 1;                    break;                 default:                    printf("find: illegal option %c\n", c);                    argc = 0;                    found = -1;                    break;             }         }     }     if (argc != 1)             printf("Usage: find -x -n pattern\n");     else         while(my_getline(line,MAXLINE) > 0){             lineno++;             if ((strstr(line, *argv) != NULL) != except){                 if (number)                     printf("%ld", lineno);                 printf("%s", line);                 found++;             }         }     return found;  }  

Hope the C program to be read is not complex.

https://stackoverflow.com/questions/67239262/my-question-about-the-question-itself-of-kr-c-book-exercise-6-2 April 24, 2021 at 12:12PM