input redirection <

I wrote a standard i/o program which was taken from "c for dummies"

Code:

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#include <stdio.h>

int main()

{
        char ch;       
       
        while ((ch = fgetc(stdin)) != EOF)
                fputc(ch,stdout);

        return(0);
}

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I saved it as io.c and ran the program

Also, I created a new text file called text.txt and wrote the words

Code:

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Hello. I am a text file

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However, when I want to redirect stdin with

Code:

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io < text.txt,

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bash says that command io is not found.

Any ideas on how to resolve this?
I tried cat < text.txt and it works fine.

But a few pages later another command is shown ls -l | underline where underline is a program that I created, and again it shows that udnerline command is not found

Tell me how you compiled the program. Give the compiler and options you used if at all possible.

thanks foir your reply
I compiled via

cc io.c -o io

version is

Code:

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Using built-in specs.
Target: i386-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-libgcj-multifile --enable-languages=c,c++,objc,obj-c++,java,fortran,ada --enable-java-awt=gtk --disable-dssi --disable-plugin --with-java-home=/usr/lib/jvm/java-1.4.2-gcj-1.4.2.0/jre --with-cpu=generic --host=i386-redhat-linux
Thread model: posix
gcc version 4.1.2 20080704 (Red Hat 4.1.2-51)

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As the executable is in the current directory, you have to give "./io <text.txt"

Quote:

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Originally Posted by manasij7479

As the executable is in the current directory, you have to give "./io <text.txt"

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That assumes the current working directory is not included in the path (the "./" is optional if it is). Which, admittedly, is good practice for several reasons.

Code:

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char ch; 
   
while ((ch = fgetc(stdin)) != EOF)

---

The fgetc function returns an int, not a char. This can be important when comparing against EOF.

Quote:

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Originally Posted by hk_mp5kpdw

The fgetc function returns an int, not a char. This can be important when comparing against EOF.

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It is important when comparing against EOF, as EOF is generally an integral value that cannot be represented by a char. So no char can test equal to EOF.

Quote:

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Originally Posted by grumpy

It is important when comparing against EOF, as EOF is generally an integral value that cannot be represented by a char. So no char can test equal to EOF.

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If char is signed, it is certainly possible that a char can test equal to EOF, e.g., if EOF is -1. In such a case, the code that uses char may appear to be correct, but then fail when compiled elsewhere.