Me have 'C' problem...

[rjlohan]

How can I 'error check' the scanf function so that when I do:

scanf("%d", &t);

it won't go berserk if a non-decimal number (or character) is entered?

[kedaman]

not sure what you mean, i'm used to C++ and not C, but what if you scanf a string and then use atof to test the conversion

[Jim Brown]

Technical Content in Chit Chat Alert

[rjlohan]

Originally posted by Jim Brown
Technical Content in Chit Chat Alert

Bugger off!

This is what I mean:

//check scanf return value
     if (scanf("%d", &t) == 1) {
         //check for quit request
         if (t == -1) {
         //print quit message
            printf("Ok, see ya later!\n");
            return 1;
         } else if (LOW <= t <= HIGH) {
            //print translated number
            printf("%d: %s\n", t, translate(t));
         } else {
            //print error message
            printf("ERROR: %d is outside the translatable range!\n", t);
         }
     }

When scanf receives a character, it goes berserk and keeps printing some line over and over, non stop. It has to be killed.

[Jim Brown]

Originally posted by rjlohan

Bugger off!

I know you don't really mean that, and that you're just upset about Saturday's game.....

[kedaman]

I willl have a look, btw "LOW <= t <= HIGH" you're comparting a boolean (LOW<=t) with HIGH

[rjlohan]

Originally posted by kedaman
I willl have a look, btw "LOW <= t <= HIGH" you're comparting a boolean (LOW<=t) with HIGH

Ta. I didn't really know if that would work. I was gonna test it, but at this stage the scanf prob is my main one.

[rjlohan]

Originally posted by Jim Brown


I know you don't really mean that, and that you're just upset about Saturday's game.....

I'm just upset that I turned it off after 55 minutes...

[kedaman]

whatever it is, its not doing it to me, it writes both characters and numbers without problem, can you show me all of your code?

[rjlohan]

//external libraries
#include <stdio.h>
#include <errno.h>

#define LOW 1
#define HIGH 1
#define LANG "English"

//external functions
extern char* translate(int number);

//main function
int main(int argc, char* argv[])
{
  //number to be translated
  int t = -1;

  //Print title
  printf("### %s Number Translator ###\n", LANG);

  //run program
  while (1)
  { 
	 //allow user to request a number translation
	 printf("Enter a number (%d-%d) to be translated (-1 to quit):", LOW, HIGH);

	 //check scanf return value
	 if (scanf("%d", &t) != 0) {
	     //check for quit request
     	 if (t == -1) {
	 	 //print quit message
	        printf("Ok, see ya later!\n");
     	    return 1;
	     } else if ((LOW <= t) && (t <= HIGH)) {
	 		//print translated number
	 		printf("%d: %s\n", t, translate(t));
	 	 } else {
	 		//print error message
   	 		printf("ERROR: %d is outside the translatable range!\n", t);
	 	 }
	 }
  } 

  //return from program
  return 1;
}

The value of t should be passed to the external function translate if LOW <= t <= HIGH, otherwise the error message should be displayed.

It's just a simple program, but that scanf thing is a problem.

[rjlohan]

It keeps printing the line from:
printf("Enter a number (%d-%d) to be translated (-1 to quit):", LOW, HIGH);

when it goes berserk, and puts a 0 there. It's like the scanf function is never called again...

[plenderj]

Well couldn't you use %S instead in scanf

if (scanf("%S", ws) != 0) {


And then just check yourself the validity of ws ?

[rjlohan]

How do I validate a string as an integer in C?
(My C knowledge is limited...)

[plenderj]

I don't know C whatsoever, only java.
I just looked up scanf in MSDN

[rjlohan]

D'oh! Thanks anyway.

[kedaman]

well atof should return 0 if the conversion fails..
i'm still very unsure what you are trying to achieve

[rjlohan]

All the code is meant to do is accept an integer 0-10, and return the translation in a selection of languages. It's a uni assignment, the point of which is optional compilation through Unix makefiles.

This scanf thing was just causing me troubles though.

[kedaman]

well you go like this:
if (scanf("%s", s)) i= atoi(ws);
s could of course be "0", so a *s!='0' would help

[rjlohan]

Why atio(ws) when you scanned into s?

Typo?

[kedaman]

yeah sorry