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

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

???????

#define _CRT_SECURE_NO_WARNINGS#include 
   
    #include 
    
     #define MAXLINE		1000int 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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