龟etc
#include< stdio.h>
int main（int argc，char * argv []）
{
if（argc！= 2）/ * argc应为2以便正确执行* /
{
/ *我们打印argv [0]假设它是程序姓名* /
printf（" usage：％s filename"，argv [0]）;
}
else
{
//我们假设argv [1]是要打开的文件名
FILE * file = fopen（argv [1]，" r"） ;
/ * fopen返回0，NULL指针，失败时* /
if（file == 0）
{
printf（无法打开文件\ n）;
}
其他
{
unsigned char x;
/ *从文件中一次读取一个字符，在EOF停止，
其中
表示文件的结尾。请注意，
的成语为变量赋值
，检查值下面使用的是因为
赋值语句的计算结果为
赋值。 * /
while（（x = fgetc（file））！= EOF）
{
printf（"％c"，x） ）;
}
}
fclose（文件）;
}
这个程序不起作用。$ b / b
当我输入程序名称并遵循
文件名时，它会清除屏幕并显示任何内容。哪里错了？
我不确定函数fgetc 。
#include <stdio.h>
int main ( int argc, char *argv[] )
{
if ( argc != 2 ) /* argc should be 2 for correct execution */
{
/* We print argv[0] assuming it is the program name */
printf( "usage: %s filename", argv[0] );
}
else
{
// We assume argv[1] is a filename to open
FILE *file = fopen( argv[1], "r" );
/* fopen returns 0, the NULL pointer, on failure */
if ( file == 0 )
{
printf( "Could not open file\n" );
}
else
{
unsigned char x;
/* read one character at a time from file, stopping at EOF,
which
indicates the end of the file. Note that the idiom of
"assign
to a variable, check the value" used below works because
the assignment statement evaluates to the value
assigned. */
while ( ( x = fgetc( file ) ) != EOF )
{
printf( "%c", x );
}
}
fclose( file );
}
}
this program doesnt work. when i type the program name and following a
file name, it clear the screen and display nothing. where was wrong ?
and i am not sure about the function "fgetc" .
01写道：
01 wrote:
#include< stdio .H>
< snip>
else
{
unsigned char x;
/ *一次读一个字符从文件中，停止在EOF，
表示文件的结尾。请注意，为变量赋值
，检查值的成语。下面使用的是因为赋值语句的计算结果为赋值。 * /
while（（x = fgetc（file））！= EOF）
{
printf（"％c"，x）;
}
}
fclose（文件）;
}
}
这个程序不起作用。当我输入程序名称并按照
文件名时，它会清除屏幕并显示任何内容。哪里错了？
我不确定函数fgetc是什么？ 。
#include <stdio.h>
<snip>
else
{
unsigned char x;
/* read one character at a time from file, stopping at EOF, which
indicates the end of the file. Note that the idiom of "assign
to a variable, check the value" used below works because
the assignment statement evaluates to the value assigned. */
while ( ( x = fgetc( file ) ) != EOF )
{
printf( "%c", x );
}
}
fclose( file );
}
}
this program doesnt work. when i type the program name and following a
file name, it clear the screen and display nothing. where was wrong ?
and i am not sure about the function "fgetc" .
函数`fgetc`返回一个`int`，你强迫它变成`unsigned
char`。由于EOF保证是负数，你的`while`将永远运行
。屏幕实际上并不是空白，而是填充了
空白。由`printf（）`发出（实际上，无论EOF恰好是什么，一旦强制进入`unsigned char`，都是
）。你实际上是（非）幸运的，
因为没有终止''\ n''，'printf（）`可能不会产生任何输出。
将`x`更改为`int`，然后再试一次。
Function `fgetc` returns an `int`, and you''re forcing it into `unsigned
char`. As EOF is guaranteed to be negative, your `while` will run
forever. The screen does not actually go blank, but filled with
"blanks" issued by `printf()` (actually, whatever EOF happens to be
once forced into `unsigned char`). You''re actually (un)lucky it does,
as without terminating ''\n'', `printf()` may not produce any output.
Change `x` to `int`, and try again.
哦，谢谢你的帮助，它现在正常工作，thanx
Vladimir Oka写道：
oh, thank you for your help , it work now, thanx
Vladimir Oka wrote:
函数`fgetc`返回一个`int`，你强迫它进入`unsigned
char`。由于EOF保证是负数，你的`while`将永远运行
。屏幕实际上并不是空白，而是填充了空白空白。由`printf（）`发出（实际上，无论EOF恰好是什么，一旦强制进入`unsigned char`）。你实际上（非）幸运，
因为没有终止''\ n''，'printf（）`可能不会产生任何输出。
改变`x`到`int`，然后再试一次。
Function `fgetc` returns an `int`, and you''re forcing it into `unsigned
char`. As EOF is guaranteed to be negative, your `while` will run
forever. The screen does not actually go blank, but filled with
"blanks" issued by `printf()` (actually, whatever EOF happens to be
once forced into `unsigned char`). You''re actually (un)lucky it does,
as without terminating ''\n'', `printf()` may not produce any output.
Change `x` to `int`, and try again.
01写道：
01 wrote:
哦，谢谢你的帮助，现在正常工作，感谢
Vladimir Oka写道：
oh, thank you for your help , it work now, thanx
Vladimir Oka wrote:
函数`fgetc`返回一个`int`，你''强迫它进入`unsigned
char`。由于EOF保证是负数，你的`while`将永远运行
。屏幕实际上并不是空白，而是填充了空白空白。由`printf（）`发出（实际上，无论EOF恰好是什么，一旦强制进入`unsigned char`）。你实际上（非）幸运，
因为没有终止''\ n''，'printf（）`可能不会产生任何输出。
改变`x`到`int`，然后再试一次。
Function `fgetc` returns an `int`, and you''re forcing it into `unsigned
char`. As EOF is guaranteed to be negative, your `while` will run
forever. The screen does not actually go blank, but filled with
"blanks" issued by `printf()` (actually, whatever EOF happens to be
once forced into `unsigned char`). You''re actually (un)lucky it does,
as without terminating ''\n'', `printf()` may not produce any output.
Change `x` to `int`, and try again.
哦，对不起*，
oh, sorry to top-post,