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?????K&R C??????UNIX????????????????- x?- n??????????- xn?????????????????????????

??????????????????????????????- x?- n??????????????vs2015?gcc??????

???????

#define _CRT_SECURE_NO_WARNINGS
#include 
   
    
#include 
    
     
#define MAXLINE		1000
int getline_s(char *line, int max);
    
   

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 optional %c\n", c);
                    argc = 0;
                    found = -1;
                    break;
            }
        }
    }
    if (argc != 1) {
        printf("Usage: find -x -n pattern\n");
    } else {
        while (getline_s(line, MAXLINE) > 0) {
            lineno++;
            if ((strstr(line, *argv) != NULL) != except) {
                if (number)
                    printf("%ld:", lineno);
                printf("%s", line);
                found++;
            }
        }
    }
    return found;
}
int getline_s(char *s, int max){
    int c;
    char *p = s;
    while ((c = getchar()) != EOF && c != '\n') {
        *s++ = c;
    }
    if (c == '\n') {
        *s++ = c;
    }
    *s = '\0';
    return s - p;
}

????????????????

./a.out -x -n test

???????

./a.out test

???????- xn ???

./a.out -xn

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