<div>
&gt;&gt; printf(&quot;%s\t%f\n&quot;, temp_string,&amp;a); 
 
Try : 
 
&nbsp; &nbsp; &nbsp; &nbsp; printf(&quot;%s\t%f\n&quot;, temp_string, a);
</div>

<div>
So : 

<pre><code class="code-10 nolinks" id="code-122139">FILE *file_input = 0;
file_input = fopen(filename, &quot;r&quot;);
if (file_input == NULL) {
 return 1;
}
 
double a = 0.0;
char string[100];
char temp_string[30];
while (fgets(string, sizeof(string), file_input) != NULL) {
 sscanf(string, &quot;%s\t%lf&quot;, temp_string, &amp;a);
 fputs(string, stdout);
 printf(&quot;%s\t%lf\n&quot;, temp_string, a);
}
</code></pre>
</div>

<div>
Ok, if I take out the &amp;&nbsp;before the a I get a segfault, after your suggestion, I tried the following and it still doesn't work. 
 
&nbsp;sscanf(string,&quot;%s%lf&quot;,temp_string,&amp;a); 
&nbsp;sscanf(string,&quot;%s\t%lf&quot;,temp_string,&amp;a); 
&nbsp;sscanf(string,&quot;%s %lf&quot;,temp_string,&amp;a); 

</div>

<div>
&gt;&gt; Ok, if I take out the &amp;&nbsp;before the a I get a segfault, 
 
Notice that my post was about the printf, not the sscanf !
</div>

<div>
&gt;&gt; I tried the following and it still doesn't work. 
 
You have to fix both the sscanf and the printf ! See the code I posted. Try that.
</div>

<div>
Hey thanks, taking out the &amp;&nbsp;before the a in the printf fixed the problem! Good Job and thanks! &nbsp; So do you know why the file is printing out twice?
</div>

<div>
&gt;&gt; So do you know why the file is printing out twice? 
 
Because you told it to : 
 
Once here : 
 
&nbsp; fputs(string, stdout); 
 
and once here : 
 
&nbsp; printf(&quot;%s\t%lf\n&quot;, temp_string, a); 

</div>

<div>
Ah, you mean that it scans the whole file twice ? For that, I'll need to see a bit more code. Can you show the complete code ? Or at least the part that reads the file ?
</div>

<div>
 Is it a tab or somethng else between the string and the number? 
try 
&nbsp; sscanf(string,&quot;%s%lf&quot;,temp_string,&amp;a); 
&nbsp; fputs(string, stdout); 
&nbsp; printf(&quot;%s\t%f\n&quot;, temp_string,a); 

</div>

<div>
I have included the part that reads in the file, &nbsp; I know it doubles it up because I used BOTH printf and fputs, but it prints the whole file twice. Ex: 
 
1 
1 
2 
2 
3 
3 
4 
4 
5 
5 
1 
1 
2 
2 
3 
3 
4 
4 
5 
5 

</div>

<div>
&gt;&gt; but it prints the whole file twice. Ex: 
 
Yes. But as I said : I need to see a bit more code for that ... One way this could be happening is if you had a function that reads the file, and you call the function twice ...
</div>

<div>
I'm currently working on this so there are a few loose ends and no comments. 
 
 
 
#include 
#include 
#include 
#include 
 
#define MAX_SIZE_FN 15 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;// must be 15 - error check on filename! &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 
 
int getFilename( char fn[], char a[] ); &nbsp; &nbsp; &nbsp; // return int for error check &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 
int readFile( char fn[ ]); 
double convertToKM( double a ); 
double convertToMiles( double a ); 
 
int main(int argc, char *argv[]){ 
&nbsp; char filename[MAX_SIZE_FN]; 
&nbsp; char a[MAX_SIZE_FN]; 
&nbsp; &nbsp; &nbsp; if (argc&gt;2){ 
&nbsp; &nbsp; &nbsp; printf(&quot;ERROR, can only pass one arguement\n&quot;); 
&nbsp; &nbsp; &nbsp; return 0; 
&nbsp; &nbsp; &nbsp; } 
 
getFilename(filename,argv[1]); 
&nbsp;if (readFile(filename)==1){ 
&nbsp; &nbsp;printf(&quot;Error opening file, exiting\n&quot;); 
&nbsp; &nbsp;return 0;} 
readFile(filename); 
 
} 
int getFilename(char filename[MAX_SIZE_FN],char a[MAX_SIZE_FN]) { 
&nbsp; char c; 
&nbsp; if (strlen(a)&gt;15){ 
&nbsp; &nbsp; printf(&quot;The filename is too long, it must be under 15 characters\n&quot;); 
&nbsp; &nbsp; return 0;} 
&nbsp; strcpy(filename,a); 
} 
 
int readFile(char filename[MAX_SIZE_FN]){ 
 
&nbsp; FILE *file_input; 
&nbsp; file_input=fopen(filename,&quot;r&quot;); 
&nbsp; if (file_input == NULL){ 
&nbsp; &nbsp; return 1;} 
&nbsp; double a = 0; 
&nbsp; &nbsp; char string [100]; 
&nbsp; &nbsp; char temp_string[30]; 
&nbsp; &nbsp; fgets(string,sizeof(string),file_input) 
&nbsp; &nbsp; &nbsp; sscanf(string,&quot;%s&quot;,temp_string); 
&nbsp; &nbsp; &nbsp; printf(&quot;%s\tMiles\tKilometers\n&quot;, temp_string,a); 
 
 
&nbsp; &nbsp; &nbsp; while (fgets(string,sizeof(string),file_input)!=NULL){ 
&nbsp; &nbsp; &nbsp; &nbsp; if (a=0) 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; printf(&quot;&quot;); 
&nbsp; &nbsp; &nbsp; &nbsp; else 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; sscanf(string,&quot;%s\t%lf&quot;,temp_string,&amp;a); 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; fputs(string, stdout); 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; printf(&quot;%s\t%lf\n&quot;, temp_string,a); 
 
&nbsp; &nbsp; &nbsp;} 
 

</div>

<div>
Just remove the second readFile call.
</div>

<div>
Hey well thanks for all the help, you are very good at this. Stick around for a half hour maybe I'll have another question. I should be able to work with you just as fast too.
</div>

<div>
As long as the question is related to the original question, I'll be happy to answer it in here. Otherwise, it's best to open a new question, and close this one.
</div>

<div>
fyi, I will be offline for the next few hours, but will be back to answer your questions then (if they haven't been answered by someone else yet).
</div>

<div>
<div class="content wysiwyg-content">
Ok, so my problem is, I am trying to use sscanf to get a string and a floating point number, however for some reason it is missing the floating point number altogether. I used BOTH fputs AND printf in the following example to illustrate what IS getting scanned in, and what is SUPPOSED to be getting scanned in. I will include the output as well. Thanks for the help guys. (This is not the whole program, this is just the guts of the function), I NEED THAT FLOATING POINT NUMBER SCANNED IN! &nbsp;A list of things I have tried is at the very bottom too. 
 
FILE *file_input; 
&nbsp; file_input=fopen(filename,&quot;r&quot;); 
&nbsp; if (file_input == NULL){ 
&nbsp; &nbsp; return 1;} 
&nbsp; &nbsp; double a; 
&nbsp; &nbsp; char string [100]; 
&nbsp; &nbsp; char temp_string[30]; 
&nbsp; &nbsp; while (fgets(string,sizeof(string),file_input)!=NULL){ 
&nbsp; &nbsp; &nbsp; sscanf(string,&quot;%s\t%f&quot;,temp_string,&amp;a); 
&nbsp; &nbsp; &nbsp; fputs(string, stdout); 
printf(&quot;%s\t%f\n&quot;, temp_string,&amp;a); 
 
OUTPUT: 
sneffels&gt; a.out example.txt 
PLANET &nbsp;AU 
PLANET &nbsp;0.000000 
Mercury 0.39 
Mercury 0.000000 
Venus &nbsp; 0.72 
Venus &nbsp; 0.000000 
Earth &nbsp; 1 
Earth &nbsp; 0.000000 
Mars &nbsp; &nbsp;1.52 
Mars &nbsp; &nbsp;0.000000 
Jupiter 5.20 
Jupiter 0.000000 
Saturn &nbsp;9.54 
Saturn &nbsp;0.000000 
Uranus &nbsp;19.18 
Uranus &nbsp;0.000000 
Neptune 30.06 
Neptune 0.000000 
Pluto &nbsp; 39.44 
Pluto &nbsp; 0.000000 
PLANET &nbsp;AU 
PLANET &nbsp;0.000000 
Mercury 0.39 
Mercury 0.000000 
Venus &nbsp; 0.72 
Venus &nbsp; 0.000000 
Earth &nbsp; 1 
Earth &nbsp; 0.000000 
Mars &nbsp; &nbsp;1.52 
Mars &nbsp; &nbsp;0.000000 
Jupiter 5.20 
Jupiter 0.000000 
Saturn &nbsp;9.54 
Saturn &nbsp;0.000000 
Uranus &nbsp;19.18 
Uranus &nbsp;0.000000 
Neptune 30.06 
Neptune 0.000000 
Pluto &nbsp; 39.44 
Pluto &nbsp; 0.000000 
 
I've tried sscanf(string,&quot;%s\t%f&quot;,temp_string,a); &nbsp; but I get a segfault 
Ive tried sscanf(string,&quot;%s%f&quot;,temp_string,&amp;a); &nbsp; without the tab character still no luck 
I've tried sscanf(string,&quot;%s %f&quot;,temp_string,&amp;a); with just a space and that doesn't work either.
</div>
</div>

Ok, so my problem is, I am trying to use sscanf to get a string and a floating point number, however for some reason it is missing the floating point number altogether. I used BOTH fputs AND printf in the following example to illustrate what IS getting scanned in, and what is SUPPOSED to be getting scanned in. I will include the output as well. Thanks for the help guys. (This is not the whole program, this is just the guts of the function), I NEED THAT FLOATING POINT NUMBER SCANNED IN!  A list of things I have tried is at the very bottom too.

FILE *file_input;
  file_input=fopen(filename,"r");
  if (file_input == NULL){
    return 1;}
    double a;
    char string [100];
    char temp_string[30];
    while (fgets(string,sizeof(string),file_input)!=NULL){
      sscanf(string,"%s\t%f",temp_string,&a);
      fputs(string, stdout);
printf("%s\t%f\n", temp_string,&a);

OUTPUT:
sneffels> a.out example.txt
PLANET  AU
PLANET  0.000000
Mercury 0.39
Mercury 0.000000
Venus   0.72
Venus   0.000000
Earth   1
Earth   0.000000
Mars    1.52
Mars    0.000000
Jupiter 5.20
Jupiter 0.000000
Saturn  9.54
Saturn  0.000000
Uranus  19.18
Uranus  0.000000
Neptune 30.06
Neptune 0.000000
Pluto   39.44
Pluto   0.000000
PLANET  AU
PLANET  0.000000
Mercury 0.39
Mercury 0.000000
Venus   0.72
Venus   0.000000
Earth   1
Earth   0.000000
Mars    1.52
Mars    0.000000
Jupiter 5.20
Jupiter 0.000000
Saturn  9.54
Saturn  0.000000
Uranus  19.18
Uranus  0.000000
Neptune 30.06
Neptune 0.000000
Pluto   39.44
Pluto   0.000000

I've tried sscanf(string,"%s\t%f",temp_string,a);   but I get a segfault
Ive tried sscanf(string,"%s%f",temp_string,&a);   without the tab character still no luck
I've tried sscanf(string,"%s %f",temp_string,&a); with just a space and that doesn't work either.

sscanf in c problem

C is a general-purpose, imperative computer programming language, supporting structured programming, lexical variable scope and recursion, while a static type system prevents many unintended operations. By design, C provides constructs that map efficiently to typical machine instructions, so it has found lasting use in applications that had formerly been coded in assembly language, including operating systems as well as various application software for computers ranging from supercomputers to embedded systems. It is distinct from C++ (which has its roots in C) and C#, and many later languages have borrowed directly or indirectly from C.