/*--------------------------
    count.c -- 使用标准 I/O
--------------------------*/

#include <stdio.h>
#include <stdlib.h>        //提供 exit() 函数原型

int main(int argc, char *argv[])
{
    int ch;        //读取文件时，储存每个字符的地方
    FILE *fp;    //文件指针
    unsigned long count = 0;

    if (argc != 2)
    {
        printf("Usage: %s filename\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    if (NULL == (fp = fopen(argv[1], "r")))
    {
        printf("Can't open %s\n", argv[1]);
        exit(EXIT_FAILURE);
    }

    while (EOF != (ch = getc(fp)))
    {
        putc(ch, stdout);        //同 putchar(ch)
        ++count;
    }

    fclose(fp);
    printf("File %s has %lu characters\n", argv[1], count);

    return 0;
}