missing output with for loop?!?!?

hello again. this is a real n00b question but why doesn't the "1.0" show up with this code?

Code:

---

#include <stdio.h>

main()
{
  float x;

  for( x = 0; x <= 1.0; x += .1 )
    printf( "%.1f  ", x );

  printf("\n");
}

---

all i get is this:

Code:

---

0.0  0.1  0.2  0.3  0.4  0.5  0.6  0.7  0.8  0.9

---

I can't think of why it doesn't work if it satisfies all the conditions (i think).

try this .....

Code:

---

#include <stdio.h>

main()
{
  float x;

  for( x = 0; x <= 1.1; x += .1 )
    printf( "%.1f  ", x );

  printf("\n");
}

---

no, i want to know why it does that. why it doesn't print out the 1.

Ahh, the inaccuracies of floating point arithmatic.

Code:

---

#include <stdio.h>

int main(void)
{
  float x;

  for( x = 0; x <= 1.0; x += .1 )
    printf( "%.20f\n", x );

  printf("%.20f\n", x);
 
  return 0;
}

/*

Output

0.00000000000000000000
0.10000000149011611938
0.20000000298023223880
0.30000001192092895510
0.40000000596046447760
0.50000000000000000000
0.60000002384185791020
0.70000004768371582030
0.80000007152557373040
0.90000009536743164060
1.00000011920928955080

*/

---

http://docs.sun.com/source/806-3568/ncg_goldberg.html
http://www.google.com/search?ie=utf-...t+inaccuracies

Quote:

---

Originally Posted by n00by

hello again. this is a real n00b question but why doesn't the "1.0" show up with this code?

Code:

---

#include <stdio.h>

main()
{
  float x;

  for( x = 0; x <= 1.0; x += .1 )
    printf( "%.1f  ", x );

  printf("\n");
}

---

all i get is this:

Code:

---

0.0  0.1  0.2  0.3  0.4  0.5  0.6  0.7  0.8  0.9

---

I can't think of why it doesn't work if it satisfies all the conditions (i think).

---

Try changing it from float to double. But before you do, if you have a debugger, step through the program and each time x is incremented, check what the value is. You will find that by the time it gets to 1, it is actually 1.000012 or something like that - it is more than one anyway.

[edit] - ah, Hammer you type too fast.. Beaten yet again. ;)

To fix the problem, change it to x < 1.05

Quote:

---

Originally Posted by sean_mackrory

To fix the problem, change it to x < 1.05

---

Code:

---

#include <stdio.h>

int main(void)
{
    double x = 0.0;

    for (x = 0.0; x <= 1.0; x += 0.1)
        printf("%0.1f\n", x);
    return 0;
}

output:

0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0

---

What's wrong with that?

~/

Oh... I never saw your post suggesting the double change. I'm downloading Dev-C++ over a 56k line (not to mention AOL) and it's taking several minutes to load pages.