#include <stdio.h>
#include <stdlib.h>
#include <math.h>
typedef double(*func_t)(double);
double polynom (double);
double cosine (double);
double exp (double);
double squareroot (double);
typedef struct values_s{
double *x;
double *funcval;
double *derivate;
long size;
} values_t;
typedef enum boolean_e{
FALSE = 0,
TRUE = 1
} boolean_t;
values_t *values_allocate(long size)
{
values_t *val=calloc(1,sizeof(values_t));
if(!val) return 0;
val->x = calloc(size,sizeof(double));
val->funcval = calloc(size,sizeof(double));
val->derivate = calloc(size,sizeof(double));
if(!val->x || !val->funcval || !val->derivate)
{
free(val);
return 0;
}
val->size = size;
return val;
}
boolean_t values_insert(values_t *val,double x1, double x2, double x3,long index)
{
boolean_t status=FALSE;
if(!val) return status;
if(index<0 || index>=val->size) return status;
val->x[index] = x1;
val->funcval[index] = x2;
val->derivate[index] = x3;
return status=TRUE;
}
boolean_t values_free(values_t *val)
{
boolean_t status=FALSE;
if(!val) return status;
free(val->x);
free(val->funcval);
free(val->derivate);
free(val);
return status=TRUE;
}
boolean_t values_print(values_t *val)
{
boolean_t status=FALSE;
long i;
if(!val) return status;
for(i=0;i<val->size;i++)
{
printf("%ld.:\t%lf\t%lf\t%lf\n",i+1,val->x[i],val->funcval[i],val->derivate[i]);
}
return status=TRUE;
}
boolean_t differentiate(values_t *val, func_t func)
{
boolean_t status=FALSE;
long i;
if(!val) return status;
for(i=0;i<val->size;i++)
val->funcval[i]=func(val->x[i]);
for(i=0;i<val->size;i++)
{
if(((val->x[i+1]-val->x[i-1])) == 0) //Nenner = 0 !
{
fprintf(stderr,"Error: Division by Zero!\n");
val->derivate[i]=0;
continue;
}
val->derivate[i]=(val->funcval[i+1]-val->funcval[i-1])/((val->x[i+1]-val->x[i-1]));
}
return status=TRUE;
}
boolean_t values_save(values_t *val)
{
boolean_t status=FALSE;
FILE *fp;
long i;
if((fp = fopen("C:\\Programme\\gnuplot\\bin\\p2ue4_diff.txt","w")))
{
if(val)
{
for(i=0;i<val->size;i++)
fprintf(fp,"%lf\t%lf\t%lf\n",val->x[i],val->funcval[i],val->derivate[i]);
}
else return status;
}
else return status;
fclose(fp);
return status=TRUE;
}
void values_plot()
{
FILE *gnuplot = popen("C:\\Programme\\gnuplot\\bin\\gnuplot -persist","w");
if (gnuplot)
{
fprintf(gnuplot, "set title 'P2-UE4: Diff'\n");
fprintf(gnuplot, "set style data lines\n");
fprintf(gnuplot, "set xlabel 'x'\n");
fprintf(gnuplot, "set ylabel 'f(x)'\n");
fprintf(gnuplot, "set yrange [-1.1:1.1]\n");
fprintf(gnuplot, "cd 'C:\\Programme\\gnuplot\\bin'\n");
fprintf(gnuplot, "plot \"p2ue4_diff.txt\" using 1:2, \"p2ue4_diff.txt\" using 1:3\n");
}
pclose(gnuplot);
}
int main()
{
long i;
values_t *tmp;
tmp=values_allocate(500);
double x=2*M_PI/500;
for(i=0;i<500;i++)
values_insert(tmp,(x*i),0,0,i);
differentiate(tmp,cosine);
values_print(tmp);
values_save(tmp);
values_plot();
values_free(tmp);
return 0;
}
