atof

**djessemoody** · 10-27-2011

I have a multi-file program(im making a rudimentary excel application based in terminal), so I wont include all of the code.

My problem involves stdlib.h.

When I put stdlib.h in the header file, and use atof, the number is seemingly random.

Ex: Put in 4.3, "78643.0000" is returned.

However, when I put stdlib.h in the functions.c file, it works fine (put in 4.3, 4.3000 returned).

Any clue what the issue might be?

This is the header file code

Code:

//file name lab7.h
#include<stdio.h>
#include<strings.h>
#include<stdlib.h>


struct column{
     int type;
     char value[25];
     };
typedef struct {
     struct column col[9];
     } matrix;


void matrixinitialize(matrix * usermatrix);
void dispsheet(matrix * usermatrix);
int  prompt(int * rowcol, matrix * usermatrix);

This is the top and atof of the functions.c file

Code:

#include "lab7.h"
.
.
.
float cell;
cell = (float)atof(usermatrix[b].col[a].value);

**quzah** · 10-27-2011

You don't need to cast atof. If you do, it's because you forgot to include the appropriate header. Make a small program that illustrates your problem, not just random bits of code.

Code:

#include<stdio.h>
#include<stdlib.h>
int main( void )
{
    char buf[ BUFSIZ ] = { "4.567" };
    float f = 0.0;

    f = atof( buf );
    printf( "f is %f\n", f );

    return 0;
}

Quzah.

**djessemoody** · 10-27-2011

OK
Assume: #include <stdlib.h> is in a header file header.h

Code:

#include "header.h"
int main(){
  char number[] = "4.3"
  float numberf = 0;

  numberf = atof(number);
  printf("%f",numberf);
}

The output if I don't include stdlib.h(just in header file) in main is:78643.000
If I do include stdlib.h in main is: 4.30000

**quzah** · 10-27-2011

It's lucky it even compiles if you don't use the header. To successfully use a function you need to know about the function. If you don't know about it, the compiler will assume everything for arguments and return values are integers.

Quzah.

**djessemoody** · 10-27-2011

I do use the header. My assignment requires me to use all #include statements in the header file, and just one #include statement in the main code, which is a reference to my header.

**quzah** · 10-27-2011

So why are you complaining about what happens when you don't use the header, if you are using the header? Who cares what happens if you don't use it?

Quzah.

**djessemoody** · 10-27-2011

No I'm saying that when I use the header to say #include <stdlib.h>, it doesn't work. I have to put #include<stdlib.h> in my functions.c program if I want it to work.

Code:

//file header.h
#include <stdlib.h>

Code:

#include "header.h"
int main()

doesn't work

Code:

#include <stdlib.h>
int main()

does work.

I need the other way to work, and was wondering if anyone had any ideas why it might not be working.

**quzah** · 10-27-2011

Originally Posted by djessemoody

No I'm saying that when I use the header to say #include <stdlib.h>, it doesn't work. I have to put #include<stdlib.h> in my functions.c program if I want it to work.

I don't believe you. Save as incredulous.h:

Code:

#include<stdio.h>
#include<stdlib.h>

Save as incredulous.c:

Code:

#include"incredulous.h"
int main( void )
{
    char right[ BUFSIZ ] = { "4.3" };
    float sure;
    
    printf( "right = %s\n", right );
    sure = atof( right );
    printf( "sure = %f\n", sure );
    
    return 0;
}

Compile and run.

Quzah.

**djessemoody** · 10-27-2011

That version works for me, however this is my output for the file im working on.

Code:

$ ./a.out
        |   A   |   B   |   C   |   D   |   E   |   F   |   G   |   H   |   I   |
---------------------------------------------------------------------------------
   1    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   2    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   3    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   4    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   5    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   6    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   7    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   8    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   9    |       |       |       |       |       |       |       |       |       |
Enter the row and column (example: E9)
 Q0-Q9 to quit
input: A3


 Old input: 
Please Enter New Input: 4.3
        |   A   |   B   |   C   |   D   |   E   |   F   |   G   |   H   |   I   |
---------------------------------------------------------------------------------
   1    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   2    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   3    |78643.000|       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   4    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   5    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   6    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   7    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   8    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   9    |       |       |       |       |       |       |       |       |       |
Enter the row and column (example: E9)
 Q0-Q9 to quit
input:

**djessemoody** · 10-27-2011

This is if I just put stdlib.h in my functions.c file

Code:

$ ./a.out
        |   A   |   B   |   C   |   D   |   E   |   F   |   G   |   H   |   I   |
---------------------------------------------------------------------------------
   1    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   2    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   3    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   4    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   5    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   6    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   7    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   8    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   9    |       |       |       |       |       |       |       |       |       |
Enter the row and column (example: E9)
 Q0-Q9 to quit
input: A3


 Old input: 
Please Enter New Input: 4.3
        |   A   |   B   |   C   |   D   |   E   |   F   |   G   |   H   |   I   |
---------------------------------------------------------------------------------
   1    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   2    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   3    |  4.300|       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   4    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   5    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   6    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   7    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   8    |       |       |       |       |       |       |       |       |       |
---------------------------------------------------------------------------------
   9    |       |       |       |       |       |       |       |       |       |
Enter the row and column (example: E9)
 Q0-Q9 to quit

**quzah** · 10-27-2011

There's a reason I told you to try a small example. Did my example work for you? (Yes.) Then the problem isn't with your header, assuming your header just has that line in it. It's with something else. So how about actually posting your code instead of random snipped bits?

Quzah.

**djessemoody** · 10-27-2011

Code:

void dispsheet(matrix * usermatrix) {
    int a = 0;
    int b = 0;
    float cell=0.0;

    printf("        |   A   |   B   |   C   |   D   |   E   |   F   |   G   |   H   |   I   |\n");
    while (a < 9){
        printf("---------------------------------------------------------------------------------\n");
        b= 0;
        printf("   %d    |",a+1);
        while(b<9){
            if(usermatrix[b].col[a].type == 0)
                printf("%7s|",usermatrix[b].col[a].value);
// ignore         if(usermatrix[b].col[a].type == 1)
// ignore            avg(b,a,usermatrix)
            else if(usermatrix[b].col[a].type == 4){
                cell = atof(usermatrix[b].col[a].value);
                printf("%7.3f|",cell);
            }
            else printf("         |");
            b++;
        }
        printf("\n");
        a++;
    }
}

Code:




# include <stdio.h>
# include <stdlib.h>
# include <strings.h>


struct column{
     int type;
     char value[25];
     };
typedef struct {
     struct column col[9];
     } matrix;


void matrixinitialize(matrix * usermatrix);
void dispsheet(matrix * usermatrix);
int  prompt(int * rowcol, matrix * usermatrix);

**stahta01** · 10-27-2011

Originally Posted by quzah

So how about actually posting your code instead of random snipped bits?

Quzah.

I second this suggestion.

I vote for improper allocation of the usermatrix array.

Tim S.

**iMalc** · 10-27-2011

Besides, the proper way to use includes is to put as few of them in the header files as possible, whilst at the same making sure that every header file has the includes it needs to compile if it were to be the first file included by a source file. Header include guards should also be used.
If you're being taught otherwise then you're being taught wrong.

**KCfromNC** · 10-28-2011

Are there spaces between # and include in the real file, or is that error introduced by posting it here?

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