aprox succesive

//Aproximari successive

#include <stdio.h>
#include <conio.h>
#include <math.h>

typedef unsigned char LOGIC;
LOGIC Aprox_Succ(float,float,float,float,float *);
float fi(float);

int main(void)
{
   float rad,ls,ld,x0,er;

   printf("\nIntroduceti ls : ");
   scanf("%f",&ls);
   printf("\nIntroduceti ld : ");
   scanf("%f",&ld);
   printf("\nIntroduceti x0 : ");
   scanf("%f",&x0);
   printf("\nIntroduceti eroarea er : ");
   scanf("%f",&er);

   if(Aprox_Succ(ls,ld,x0,er,&rad)) printf("\nSolutia este = %f",rad);
   else printf("\n Eroare");

   getch();
   return 1;
}

LOGIC Aprox_Succ(float ls,float ld,float x0,float er,float *pRad)
{
 float pc,xn,xn_1,h;
 float der;

 h=1e-2;
 pc=ls;
 do {
  der=(fi(pc+h)-fi(pc))/h;
  if(fabs(der)>=1) {return(0);}
  pc=pc+h;
 } while(pc<=ld);

 xn=x0;
 do{
  xn_1=xn;
  xn=fi(xn_1);
 } while(fabs(xn-xn_1)>er);

 *pRad=xn;
 return(1);
}

float fi(float x)
{
  return exp(-x);
}