C Primer Plus（第六版）13.11 编程练习 第9题

/*
修改程序清单13.3 中的程序，从1开始，根据加入列表的顺序为每个单词编号。当程序下次运行
时，确保新的单词编号接着上次的编号开始。

*/
//13.11-8.exe c 13.11-8.txt 13.11-8-1.txt 13.11-8-2.txt
#include
#include
#include
#define MAX 41

int get_row(char *file_name) ;

int main(void)
{
    FILE *fp;
    char words[MAX];
    int row;
    
    row = get_row("wordy");
    if ((fp = fopen("wordy", "a+")) == NULL)
    {
        fprintf(stdout,"Can't open \"wordy\" file.\n");
        exit(EXIT_FAILURE);
    }
    
    puts("Enter words to add to the file; press the #");
    puts("key at the beginning of a line to terminate.");
    while ((fscanf(stdin,"%40s", words) == 1)  && (words[0] != '#'))
        fprintf(fp, "%d-%s\n",row++, words);
    
    puts("File contents:");
    rewind(fp);           /* go back to beginning of file */
    while (fscanf(fp,"%s",words) == 1)
        puts(words);
    puts("Done!");
    if (fclose(fp) != 0)
        fprintf(stderr,"Error closing file\n");
    
    return 0;
}

int get_row(char *file_name) 
{
    FILE *fp;
    int i=1; 
    char ch;
    fp = fopen(file_name, "r");
    rewind(fp);
    while ((ch = getc(fp)) != EOF)
    {
        if (ch == '\n')
            i++;
    }
    fclose(fp);
    return i; 
}