将文件中的值添加到数组中，直到某个字符为止

Question

I am working on a program that uses file redirection to read in a file, read one character per line until I reach a '0', store the characters in an array , and sort that array (from largest to smallest). Anyway, I really only need help with reading the characters until the zero shows up. Below is the text file that I am reading in:

f
k
s
j
p
a
v
r
t
u
h
m
g
e
b
y
n
z
w
l
i
x
q
c
o
d
0

Below is the code I have so far:

int main(void)
{
    int i=0;
    char array[100];

    while(fscanf(stdin, "%c", &array[i]) && array[i]!='0')
    {
        i++;
    }

    int N = (sizeof(array)/sizeof(array[0]));

    for(i=0;i<N;i++)
    {
        printf("%c", array[i]);
    }

return(0);
}

When I run this program, it prints out every line of the file, including the zero. It also prints out some really weird characters after the zero (using gcc compiler). What am I doing wrong?

Answer 1

您需要将N设置为i的值，当前始终为100

Answer 2

You use i to keep track of how many items you've read, but then you overwrite the value of i in your loop and print out all 100 elements, whether you stored something there or not.

Use different variable for counting the element than you do for looping, and use the count as your loop limit.

int count=0;
char array[100];

while(fscanf(stdin, "%c", &array[count]) && array[count]!='0')
{
    count++;
}

for(i=0;i<count;i++)
{
    printf("%c", array[i]);
}

Answer 3

fscanf needs to skip the separator (enter or space), else it will be incorporated into your list. Adding a space fixes that.

#include <stdio.h>
#include <stdlib.h>

int sort (const void *a,const void *b)
{
    return ((int)*((unsigned char *)a)) - ((int)*((unsigned char *)b));
}

int main (void)
{
    unsigned char array[100],i=0;
    while (fscanf(stdin," %c", &array[i]) && array[i] != '0')
        i++;
    qsort (array,i,1,sort);
    while (i)
        printf ("%c\n", array[--i]);
}

It may seem this program sorts the wrong way around but the printing loop also happens to print in reverse, so that solves it neatly. As the array is unsigned char, the sort routine casts this to int to prevent possible overflow.