Question

我已经提供了一个用于程序的CSV行解析器，它似乎有一个错误，如果文本文件末尾有一个空行，它会打印出一个空行，就像这样

我的输入是

test, does, this, work
1, second, line, same

我的输出看起来像这样。它不仅切断了最后一个字，而且打印出空行。

test = 1
 does =  second
 this =  line
 work =  same
test =

它应该做的是将每个单词与顶行中重合的单词匹配，但是我不知道最后一个“test =”来自哪里。这是我提供的代码，任何有关它的错误的想法都将是一个巨大的帮助。感谢。

/*
 * Just an array of characters representing a single filed.
 */

typedef char f_string[MAX_CHARS+1] ;    /* string for each field */

/*
 * A parsed CSV line, with the number of fields and upto MAX_FIELDS themselves.
*/

typedef struct {
    int nfields ;               /* 0 => end of file */
    f_string field[MAX_FIELDS] ;        /* array of strings for fields */
} csv_line ;

/*
 * Returns true iff the character 'ch' ends a field. That is, ch is end of file,
 * a comma, or a newline.
 */

bool is_end_of_field(char ch) {
    return (ch == ',') || (ch == '\n') || (ch == EOF) ;
}

/*
 * Return the minimum of two integers.
 */

int min(int x, int y) {
    return x < y ? x : y ;
}

/*
 * Read the next field from standard input. Returns the value of getchar() that
 * stopped (terminated) the field.
 */

int get_field(f_string field) {
/**BEGIN_SOLN**/
    int i ;
    int next_char ;

    next_char = getchar() ;
    for ( i = 0 ; ! is_end_of_field(next_char) ; ++i ) {
        field[i] = next_char ;
        next_char = getchar() ;
    }

    field[i] = '\0' ;
    return next_char ;
/**END_SOLN**/
}

/*
 * Read in a CSV line. No error checking is done on the number of fields or
 * the size of any one field.
 * On return, the fields have been filled in (and properly NUL-terminated), and
 * nfields is the count of the number of valid fields.
 * nfields == 0 means end of file was encountered.
 */

csv_line get_line() {
/**BEGIN_SOLN**/
    csv_line line ;
    int fi = 0 ;    /* index of current field in line */
    int stop_ch ;   /* character that terminated the last field */

    stop_ch = get_field(line.field[fi++]) ;
    while ( stop_ch == ',' ) {
        stop_ch = get_field(line.field[fi++]) ;
    }

    line.nfields = (stop_ch == EOF) ? 0 : fi ;
    return line ;
/**END_SOLN**/
}

/*
 * Print a CSV line, associating the header fields with the
 * data line fields.
 * The minimum of the number of fields in the header and the data
 * determines how many fields are printed.
 */

void print_csv(csv_line header, csv_line data) {
/**BEGIN_SOLN**/
    int i ;
    int nfields = min(header.nfields, data.nfields) ;

    for ( i = 0 ; i < nfields ; ++i ) {
        printf("%s = %s\n", header.field[i], data.field[i]) ;
    }
/**END_SOLN**/
}

/*
 * Driver - read a CSV line for the header then read and print data lines
 * until end of file.
 */

int main() {
    csv_line header ;
    csv_line current ;

    header = get_line() ;
    current = get_line() ;

    while ( current.nfields > 0 ) {
        print_csv(header, current) ;
        current = get_line() ;
    }

    return 0 ;
}

Answer 1

bool is_end_of_field(int ch) {
    return (ch == ',') || (ch == '\n') || (ch == EOF) ;
}

bool get_field(f_string field){
    int i ;
    int next_char ;
    for ( i = 0 ; ! is_end_of_field(next_char=getchar()) ; ++i ) {
        field[i] = next_char ;
    }
    field[i] = '\0';
    return (next_char == ',')? true :  false;
}

csv_line get_line() {
    csv_line line ;
    int fi = 0;
    while(get_field(line.field[fi++]))
        ;
    line.nfields = line.field[fi-1][0] ? fi : 0;
    return line ;
}

csv行解析，最后打印额外的行

1 个答案: