/*******************************************************************//*                                                                 *//* test environment for the function null(); null() calculates     *//* the roots of a polynomial with complex coefficients with a      *//* combination of muller method and newton method                  *//*                                                                 *//*******************************************************************/#define TEST#include "header.h"                      /* read coefficients stored in file FILENAME */void datei_einlesen(int *grad)/*int *grad;             delivers degree of polynomial             */{     FILE *fp;        /* filepointer                               */     int  i;          /* counter                                   */                      /* open file                                 */     if ((fp = fopen(FILENAME,MODE)) == NULL) {          printf("Can't open file %s!\n",FILENAME);          return;     } else {                      /* read file: file format:                   */                      /* degree | Flag | RE(a0) ... | RE(an)       */                      /*                 IM(a0)...  | IM(an)       */                       /* read degree                               */          (void) fscanf(fp,"%d",grad);                      /* read flag                                 */          (void) fscanf(fp,"%d",&flag);                      /* read coefficients                         */          for (i=0; i<=(*grad); i++) {               (void) fscanf(fp,"%le",&(p[i].r));          if (flag) {               for (i=0;i<=(*grad); i++)                    (void) fscanf(fp,"%le",&(p[i].i));               }          }                      /* close file                                */          (void) fclose(fp);     }}                           /* read coefficients from terminal           */void tastatur_einlesen(int *grad)/*int *grad;*/{     int i;           /* counter                                   */     char ent;        /* read choice                               */                       /* enter degree of polynomial                */     printf("Please enter degree: ");     (void) scanf("%d",grad);     printf("Enter coefficients a0 ... an:\n");                      /* Realteilabfrage                           */     printf("real parts:\n");     for (i=0; i<=(*grad); i++) {          printf("a%d (real part): ",i);          (void) scanf("%le",&(p[i].r));     }     printf("Exists also imaginary parts (y/n)? ");     (void) scanf("%c",&ent);    /* clear keyboard                */     (void) scanf("%c",&ent);    /* ans choice                    */                                 /* complex coefficients          */     if (ent == 'y' || ent == 'Y') {          printf("imaginary parts:\n");          for (i=0; i<=(*grad);i++) {               printf("a%d (imaginary part): ",i);               (void) scanf("%le",&(p[i].i));          }     } else flag = FALSE;        /* real coeff. => flag = FALSE   */}                      /* main loop                                 */char main(void) {     double maxerr;   /* max. error of all determined roots        */     unsigned char   error;     char   sig1,     /* signum of real part                       */            sig2,     /* signum of imaginary part                  */            ent;      /* read choice                               */      int    degree,   /* degree of polynomial                      */            i;        /* counter variable                          */     FILE   *fp;      /* file pointer                              */     printf("Input from file %s (y/n)?\n",FILENAME);     (void) scanf("%c",&ent);     if (ent == 'y' || ent == 'Y')           datei_einlesen(&degree);     else          tastatur_einlesen(&degree);     error=null(p,pred,&degree,root,&maxerr,(unsigned char)flag);     if (!error) {                                /* generate matlab-file */       fp=fopen("null.m","w");        fprintf(fp,"re=[");       for (i=1;i<=degree; i++)             fprintf(fp,"%.18e\n",root[i-1].r);       fprintf(fp,"];\nim=[");       for (i=1;i<=degree; i++)            fprintf(fp,"%.18e\n",root[i-1].i);       fprintf(fp,"];\ni=sqrt(-1);\nnull=re+i*im;\npn_plot(null,0)");       (void) fclose(fp);                               /* write stdoutput */        for (i=1;i<=degree; i++) {          sig1=(root[i-1].r>=0) ? ' ':'-';          sig2=(root[i-1].i>=0) ? ' ':'-';          printf("%3d. root:    %c%.18e     %c%.18e\n",i,          sig1,fabs(root[i-1].r),sig2,fabs(root[i-1].i));       }       printf("max. error: %.18e\n",maxerr);     } else {          printf("Error %d occured!\n",(int)error);          switch (error) {          case 1:               printf("Power of polynomial lower null!\n");               break;          case 2:               printf("Polynomial is a null vector!\n");               break;          case 3:               printf("Polynomial is a constant unequal null!\n");               break;          }          return 1;     }     return 0;        /* no error occured       */}