- #1
epr2008
- 44
- 0
I have been working on coding a program that works for all bases, including non-integers. I have been checking it against wolframalpha, and so far, my code works for a decent amount of bases, but at the same time has trouble with others... For instance it seems to have a tolerance in the magnitude and the digit length of the bases. So, far I have tested and it seems to work for bases larger than 1.5 (I have tested it up to 64 so far) and up to 6 digit bases(6 including the digits after the decimal) with some exceptions. I have noticed that for the decimal bases that my program computes that don't match wolfram, the string will match until a certain digits place, say k, and at k, k-1 wolfram will have a 10 respectively, while my computed value will have the floor of the base in the k-1 place. I figured that it may be that my algorithm wasn't finding the highest power divisor right, but then I realized that would not make since. So, I was hoping that fresh eyes may be able to help me out with it... By the way, this is just a rough draft, but the procedure should be fairly simple to follow.
Code:
#include <stdio.h>
#include <math.h>
void convert_base(double x, double b)
{
double y, z;
int digit, i, j = 0, k;
/* Find the terms in power series expansion with base power > 0 */
z = x;
while(z >= 1)
{
/* Compute largest power of base which divides x giving a value >= b*/
y = z;
digit = y;
i = 0;
while(digit >= b)
{
y = y / b;
digit = y;
i++;
//printf("y = %lf\n", y);
}
//printf("i = %d\n", i);
//printf("digit = %d\n", digit);
/* Subtract off this term in series expansion */
z = z - (digit * pow(b, i));
//printf("z = %lf\n", z);
/* Fill in digits in between the last calculated digit and this calculated digit */
if((abs(i - j) > 1) && (j != 0))
{
for(k = 1; k < abs(i - j); k++)
{
printf("0");
}
}
printf("%d", digit);
j = i;
}
if(j != 0)
{
for(k = j; j > 0; j--)
{
printf("0");
}
}
printf(".");
/* Find the terms in the power series expansion with base power < 0 */
while((z > 0) && (z <= 1) && (i > -6))
{
/* Compute smallest power of base which multiplies x giving a value >1 */
y = z;
digit = y;
i = 0;
while(digit < 1)
{
y = y * b;
digit = y;
i--;
//printf("y = %lf\n", y);
}
//printf("i = %d\n", i);
//printf("digit = %d\n", digit);
/* Subtract off this term in series expansion */
z = z - (digit * pow(b, i));
//printf("z = %lf\n", z);
/* Fill in digits in between the last calculated digit and this calculated digit */
if(abs(i - j) > 1)
{
for(k = 1; k < abs(i - j); k++)
{
printf("0");
}
}
printf("%d", digit);
j = i;
}
if(z == 0)
{
printf("000");
}
printf("...\n");
}
int main(void)
{
double x, b;
printf("Enter a number: x = ");
scanf("%lf", &x);
printf("Enter the base for conversion: b = ");
scanf("%lf", &b);
printf("(x)_b = %lf = ", x);
convert_base(x, b);
return 0;
}
