Ceil function in C

[sivaranjan]

I am not having much knowledge about the C language, so thought asking you guys will might solve my problem. I am trying to get the ceil function working in Dev-C++. And I am using the C language for that. I know that the Dev-C++ is compatible for C and C++ languages. When I type in a recognized word for example int or double it turns bold. But when typing in the ceil function it does not turn bold, I am including the <math.h> header file.!! Why is it that i can't seem to get it to work what am i doing wrong.?? Is it that its not a proper function in Dev-C++?? Please help me for solving the issue.

[Zecho]

You can use the following example of the Ceil Function :

/* ceil example */
#include <stdio.h>
#include <math.h>

int main ()
{
  printf ("ceil of 2.6 is %.1lf\n", ceil (2.6) );
  printf ("ceil of 3.7 is %.1lf\n", ceil (3.7) );
  printf ("ceil of -2.6 is %.1lf\n", ceil (-2.6) );
  printf ("ceil of -3.7 is %.1lf\n", ceil (-3.7) );
  return 0;
}

Check using this example and I am sure that your problem will be fixed.

[void]

I was facing the similar problem in C language. Later I realized that the problem was coming because I set my variable x of ceil(x) as int. I then set that variable x of ceil(x) as double. So when I input a double number, it was reading the first digit only, leaving me the incorrect output. Hope that will help too. I don't think that there is some problem with your Dev-C++. Since it is good compiler and supports both C and C++ language. I think that you will have to make some changes in your code.

[Allan.d]

Even I don't think that your Dev-C++ is having some problem. Even if you think that there is some problem with that then try to reinstall the application. You can also the following code, which can fix your problem.

#include <math.h>

double result = ceil( 0.5 );
// result now contains 1.0.

[Praetor]

I am providing you with an another example. Hope that it helps you. Here is the code for that :

int CEIL(double var)
{
int integer = (int)var;
if(var - integer == 0) return integer;
else return integer + 1;
}

Also you can write your own macro, if you think that compiler is causing some issue. It will look like this :

#define CEIL(VARIABLE) ( (VARIABLE - (int)VARIABLE)==0 ? (int)VARIABLE : (int)VARIABLE+1 )

[Katty]

I have tried to do declare an array (arr[4]) and use ceil and floor function. The result came out fine, if the number is not zero. Here is the coding for that :

# include <math.h> 
int main(){
float arr[4],c[4];
int i;
 
arr[0]=-2.828427; arr[1]=-0.707107; arr[2]=0.000000;arr[3]=-0.707107;
 
for (i=0;i<4;i++){
c[i]=ceil (arr[i]);
printf ("%f\n",c[i]);
}
  
}

Hope that you will get some hint after looking at this example.