Thread: Resistance Calculator , my resistor values are wrong at the end for calculation2&3

Code:

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main()






{
    char c1, c2, c3, c4, c5, c6, choicenew;
    int choiceRs;
    float RsP,Rs3,Rs2,Rs1,choiceSP3,choiceSP2,choiceSP1,choiceSP=0,choiceRs3,choiceRs2,choiceRs1,rone3,rone2,rone1,rtwo3,rtwo2,rtwo1,rthree3,rthree2,rthree1;
    printf("-----------------------------------------------------------------------------------------------------------------------\n");
    printf("Project Done By:123\nProject Title: Resistance Calculator\n");
    printf("-----------------------------------------------------------------------------------------------------------------------\n");
    start:
    printf("Enter 6 secret Number(PASSWORD): \n");
    c1 = getch(); putchar('*');
    c2 = getch(); putchar('*');
    c3 = getch(); putchar('*');
    c4 = getch(); putchar('*');
    c5 = getch(); putchar('*');
    c6 = getch(); putchar('*');


             if (c1 == '1' && c2 == '2' && c3 == '3' && c4 == '4' && c5 == '5' && c6 == '6')
        {
            printf("\nWelcome to Equivalent Resistance Calculator!!! \n");


            printf("\nYou're advised to Calculate 3 times for proper Summary\n");
        }
        else
        {
          printf("\n You have entered wrong Password!\n");
          goto start;




        }
        /* printf("\nSshhh!! Secret letters you typed are: %c%c%c%c%c%C", c1, c2, c3, c4, c5, c6);*/








select:
         printf("\nSelect Either Series or Parallel Circuit\n");
         printf("\nPress 1 for Series Circuit \nPress 2 for Parallel Circuit\n ");


 {


        int choiceSP, i;
        float r[3] , RsS = 0;
        start2:
        scanf("%d",&choiceSP);


        choiceSP3=choiceSP2;
        choiceSP2=choiceSP1;
        choiceSP1=choiceSP;




switch (choiceSP)


{
case 1 :
        printf("You have chosen *Series Circuit* ");


{
         printf("\nEnter the number of Resistors in your circuit:\n ");
         printf("\nPress 1 for 2 Resistors \nPress 2 for 3 Resistors \n ");


                 int choiceRs;
                 start3:
                 scanf("%d",&choiceRs);


                 choiceRs3=choiceRs2;
                 choiceRs2=choiceRs1;
                 choiceRs1=choiceRs;




switch (choiceRs)


                {
                case 1 :
                  printf("\nYou have chosen *2 Resistors*");
{
                  {


                    printf("\nEnter Value of Each Resistor (in Ohm) : \n");


                    for (i = 0; i < 2; i++)
                      {
                        printf("\nR%d : ", i + 1);
                        scanf("%f", &r[i]);
                       rone3=rone2;
                       rone2=rone1;
                       rone1=r[0];
                       rtwo3=rtwo2;
                       rtwo2=rtwo1;
                       rtwo1=r[1];
                       rthree3=rthree2;
                       rthree2=rthree1;
                       rthree1=r[2];
                      }


                    for (i = 0; i < 2; i++)
                    {
                    RsS = RsS + r[i];
                    }


                    printf("\nEquivalent Series Resistance = %.4f Ohm", RsS);


                                                                Rs3=Rs2;
                                                                Rs2=Rs1;
                                                                Rs1=RsS;
                    getch();
                    system("CLS");
YN1 :
{
       printf("\nDo you want to calculate a new one?\n");
       printf("\nPress Y for *Yes* and N for *No* (End Program after showing summary)\n");
       fflush(stdin);
       scanf("%c", &choicenew);


       system("CLS");
  {




       if (choicenew == 'Y' || choicenew == 'y')
           {
            goto select;
           }
       else if (choicenew == 'N' || choicenew == 'n')
           {
            goto summary;
            break;
           }
       else if (choicenew != 'Y' || choicenew != 'y' || choicenew != 'N' || choicenew != 'n')
           {
            printf("Please choose either Y or N");
            goto YN1;
           }


  }


}
                      }
                     break;




                    case 2 :
                    printf("\nYou have chosen *3 Resistors*");
                    {
                    {
                         printf("\nEnter Value of Each Resistor (in Ohm)  : \n");


                         for (i = 0; i < 3; i++)
                       {
                        printf("\nR%d : ", i + 1);
                        scanf("%f", &r[i]);


                      rone3=rone2;
                       rone2=rone1;
                       rone1=r[0];
                       rtwo3=rtwo2;
                       rtwo2=rtwo1;
                       rtwo1=r[1];
                       rthree3=rthree2;
                       rthree2=rthree1;
                       rthree1=r[2];


                       }
                       for (i = 0; i < 3; i++)
                       {
                       RsS = RsS + r[i];
                       }


                    printf("\nEquivalent Series Resistance = %.4f Ohm", RsS);


                                                                      Rs3=Rs2;
                                                                      Rs2=Rs1;
                                                                      Rs1=RsS;


                    getch();
                    system("CLS");


YN2 :
 {
      printf("\nDo you want to calculate a new one?\n");
      printf("\nPress Y for *Yes* and *N* for No (End Program after showing summary) \n");
      fflush(stdin);
      scanf("%c", &choicenew);
      system("CLS");
      if (choicenew == 'Y' || choicenew == 'y')
         {
          goto select;
         }
      else if (choicenew == 'N' || choicenew == 'n')
         {
          goto summary;
          break;
         }
      else
         {
          printf("Please choose either Y or N");
          goto YN2;
         }


 }


                        }
                            }


break;
default:
printf("Sorry you are only allowed to choose either 2 or 3 resistors\n");


goto start3;
break;


}


                            }
                            break;
case 2 :
               printf("You have chosen *Parallel Circuit*");
               float RsP = 0, invRsP = 0;
            {
              printf("\nEnter the number of Resistors in your circuit:\n ");
              printf("\nPress 1 for 2 Resistors \nPress 2 for 3 Resistors \n ");


                int choiceRs;
                start4:
                scanf("%d",&choiceRs);
                 choiceRs3=choiceRs2;
                 choiceRs2=choiceRs1;
                 choiceRs1=choiceRs;


switch (choiceRs)






{
    case 1 :
    printf("\nYou have chosen *2 Resistors*");
    /*float r[10];*/


 {
     {
     printf("\nEnter Value of Each Resistor (in Ohm)  : n");
     for (i = 0; i < 2; i++)
     {
     printf("\n R%d : ", i + 1);
     scanf("%f", &r[i]);
       rone3=rone2;
                       rone2=rone1;
                       rone1=r[0];
                       rtwo3=rtwo2;
                       rtwo2=rtwo1;
                       rtwo1=r[1];
                       rthree3=rthree2;
                       rthree2=rthree1;
                       rthree1=r[2];
     }
     for (i = 0; i < 2; i++)
     {
     invRsP+=(1.0/r[i]);
     }
     RsP=(1.0/invRsP);
     }


     printf("\nEquivalent Parallel Resistance = %.4f Ohm", RsP);


                                                        Rs3=Rs2;
                                                        Rs2=Rs1;
                                                        Rs1=RsP;


       getch();
       system("CLS");
YN3:
{




    printf("\nDo you want to calculate a new one?\n");
    printf("\nPress Y for *Yes* and N for *No* (End Program after showing summary)\n");
    fflush(stdin);
    scanf("%c", &choicenew);
    system("CLS");
    if (choicenew == 'Y' || choicenew == 'y')
    {
     goto select;
    }
    else if (choicenew == 'N' || choicenew == 'n')
    {
     goto summary;
     break;
    }
    else
     {
       printf("Please choose either Y or N");
       goto YN3;
     }
}
}
break;
            case 2 :
              printf("\nYou have chosen *3 Resistors*");
{
        {
             printf("\nEnter Value of Each Resistor (in Ohm) : \n");
             for (i = 0; i < 3; i++)
            {
             printf("\n R%d : ", i + 1);
             scanf("%f", &r[i]);


             rone3=rone2;
                       rone2=rone1;
                       rone1=r[0];
                       rtwo3=rtwo2;
                       rtwo2=rtwo1;
                       rtwo1=r[1];
                       rthree3=rthree2;
                       rthree2=rthree1;
                       rthree1=r[2];
            }
            for (i = 0; i < 3; i++)
            {
             invRsP+=(1.0/r[i]);
            }
            RsP=(1.0/invRsP);
        }


        printf("\nEquivalent Parallel Resistance = %.4f Ohm", RsP);


                                                            Rs3=Rs2;
                                                            Rs2=Rs1;
                                                            Rs1=RsP;
            getch();
            system("CLS");
YN4:
{
       printf("Do you want to calculate a new one?");
       printf("\nPress Y for *Yes* and N for *No* (End Program after showing summary)\n");
       fflush(stdin);
       scanf("%c", &choicenew);
       system("CLS");
       if (choicenew == 'Y' || choicenew == 'y')
      {
      goto select;
      }
      else if (choicenew == 'N' || choicenew == 'n')
      {
       goto summary;
       break;
      }
      else
      {
       printf("Please choose either Y or N");
       goto YN4;
      }


}
}


       break;
default:
printf("Sorry you are only allowed to choose either 2 or 3 resistors\n");
goto start4;
break;


}
}
       default:
       printf("Sorry please choose either 1 or 2 \n");
       goto start2;
       break;
}


summary:


    system("COLOR CF");


    printf("---------------------------------------------------------------------------------------------------------------------");
    printf("\nTake Note :");
    printf("\n\nCircuit type:\n1 = Series Circuit &\n2 = Parallel Circuit\n\n");
    printf("\nCalculation 1 is the latest while Calculation 3 was the earliest");
    printf("\n---------------------------------------------------------------------------------------------------------------------\n");


    printf("\nCalculation 1 : Equivalent Resistance = %.4f Ohm You chose Circuit type %.f  and %.f Resistors  \nR1=%.f, R2=%.f, R3=%.f\n",Rs1,choiceSP1,choiceRs1 + 1, rone1, rtwo1, rthree1);
    printf("\nCalculation 2 : Equivalent Resistance = %.4f Ohm You chose Circuit type %.f  and %.f Resistors  \nR1=%.f, R2=%.f, R3=%.f\n",Rs2,choiceSP2,choiceRs2 + 1, rone2, rtwo2, rthree2);
    printf("\nCalculation 3 : Equivalent Resistance = %.4f Ohm You chose Circuit type %.f  and %.f Resistors  \nR1=%.f, R2=%.f, R3=%.f\n",Rs3,choiceSP3,choiceRs3 + 1, rone3, rtwo3, rthree3);
    printf("\n*********************************************************************************************************************\n");


    printf("                                                THANK YOU!!!!                                                            ");


    printf("*********************************************************************************************************************");
























}
} }

Well your first problem is that you have a main() which is poorly formatted, 100's of lines long AND riddled with goto's.
Whoever's been responsible for your programming education up to now has been doing a very bad job.

The whole of each case for series and parallel circuits should be separate functions.

In both cases, the 2 resistor case is just a special case of the 3 resistor case.
By suitable initialisation of the 3rd resistor value, you can prune away an awful lot of copy/paste code.

There are a whole bunch of variables which may be uninitialised.

Code:

$ gcc -Wall -Wextra -Wno-unused-result -O2 foo.c
foo.c: In function ‘main’:
foo.c:15:8: warning: implicit declaration of function ‘getch’ [-Wimplicit-function-declaration]
   c1 = getch();
        ^
foo.c:8:62: warning: unused variable ‘choiceSP’ [-Wunused-variable]
   float RsP, Rs3, Rs2, Rs1, choiceSP3, choiceSP2, choiceSP1, choiceSP =
                                                              ^
foo.c:8:9: warning: unused variable ‘RsP’ [-Wunused-variable]
   float RsP, Rs3, Rs2, Rs1, choiceSP3, choiceSP2, choiceSP1, choiceSP =
         ^
foo.c:7:7: warning: unused variable ‘choiceRs’ [-Wunused-variable]
   int choiceRs;
       ^
foo.c:293:7: warning: ‘rthree2’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       printf
       ^
foo.c:296:7: warning: ‘rthree1’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       printf
       ^
foo.c:293:7: warning: ‘rtwo2’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       printf
       ^
foo.c:296:7: warning: ‘rtwo1’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       printf
       ^
foo.c:293:7: warning: ‘rone2’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       printf
       ^
foo.c:296:7: warning: ‘rone1’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       printf
       ^
foo.c:298:38: warning: ‘choiceRs2’ may be used uninitialized in this function [-Wmaybe-uninitialized]
            Rs3, choiceSP3, choiceRs3 + 1, rone3, rtwo3, rthree3);
                                      ^
foo.c:295:38: warning: ‘choiceRs1’ may be used uninitialized in this function [-Wmaybe-uninitialized]
            Rs2, choiceSP2, choiceRs2 + 1, rone2, rtwo2, rthree2);
                                      ^
foo.c:293:7: warning: ‘choiceSP1’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       printf
       ^
foo.c:296:7: warning: ‘choiceSP2’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       printf
       ^
foo.c:293:7: warning: ‘Rs1’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       printf
       ^
foo.c:296:7: warning: ‘Rs2’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       printf
       ^

But because the code is such a rats-nest, there's no point in trying to trace through it all just to check.


Finally, some indentation.

Code:

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main()
{
  char c1, c2, c3, c4, c5, c6, choicenew;
  int choiceRs;
  float RsP, Rs3, Rs2, Rs1, choiceSP3, choiceSP2, choiceSP1, choiceSP =
      0, choiceRs3, choiceRs2, choiceRs1, rone3, rone2, rone1, rtwo3, rtwo2, rtwo1, rthree3, rthree2, rthree1;
  printf("-------------------------------------------------------------------\n");
  printf("Project Done By:123\nProject Title: Resistance Calculator\n");
  printf("-------------------------------------------------------------------\n");
start:
  printf("Enter 6 secret Number(PASSWORD): \n");
  c1 = getch();
  putchar('*');
  c2 = getch();
  putchar('*');
  c3 = getch();
  putchar('*');
  c4 = getch();
  putchar('*');
  c5 = getch();
  putchar('*');
  c6 = getch();
  putchar('*');
  if (c1 == '1' && c2 == '2' && c3 == '3' && c4 == '4' && c5 == '5' && c6 == '6') {
    printf("\nWelcome to Equivalent Resistance Calculator!!! \n");
    printf("\nYou're advised to Calculate 3 times for proper Summary\n");
  } else {
    printf("\n You have entered wrong Password!\n");
    goto start;
  }
  /* printf("\nSshhh!! Secret letters you typed are: %c%c%c%c%c%C", c1, c2, c3, c4, c5, c6); */
select:
  printf("\nSelect Either Series or Parallel Circuit\n");
  printf("\nPress 1 for Series Circuit \nPress 2 for Parallel Circuit\n ");
  {
    int choiceSP, i;
    float r[3], RsS = 0;
  start2:
    scanf("%d", &choiceSP);
    choiceSP3 = choiceSP2;
    choiceSP2 = choiceSP1;
    choiceSP1 = choiceSP;
    switch (choiceSP) {
    case 1:
      printf("You have chosen *Series Circuit* ");
      {
        printf("\nEnter the number of Resistors in your circuit:\n ");
        printf("\nPress 1 for 2 Resistors \nPress 2 for 3 Resistors \n ");
        int choiceRs;
      start3:
        scanf("%d", &choiceRs);
        choiceRs3 = choiceRs2;
        choiceRs2 = choiceRs1;
        choiceRs1 = choiceRs;
        switch (choiceRs) {
        case 1:
          printf("\nYou have chosen *2 Resistors*");
          {
            {
              printf("\nEnter Value of Each Resistor (in Ohm) : \n");
              for (i = 0; i < 2; i++) {
                printf("\nR%d : ", i + 1);
                scanf("%f", &r[i]);
                rone3 = rone2;
                rone2 = rone1;
                rone1 = r[0];
                rtwo3 = rtwo2;
                rtwo2 = rtwo1;
                rtwo1 = r[1];
                rthree3 = rthree2;
                rthree2 = rthree1;
                rthree1 = r[2];
              }
              for (i = 0; i < 2; i++) {
                RsS = RsS + r[i];
              }
              printf("\nEquivalent Series Resistance = %.4f Ohm", RsS);
              Rs3 = Rs2;
              Rs2 = Rs1;
              Rs1 = RsS;
              getch();
              system("CLS");
            YN1:
              {
                printf("\nDo you want to calculate a new one?\n");
                printf("\nPress Y for *Yes* and N for *No* (End Program after showing summary)\n");
                fflush(stdin);
                scanf("%c", &choicenew);
                system("CLS");
                {
                  if (choicenew == 'Y' || choicenew == 'y') {
                    goto select;
                  } else if (choicenew == 'N' || choicenew == 'n') {
                    goto summary;
                    break;
                  } else if (choicenew != 'Y' || choicenew != 'y' || choicenew != 'N' || choicenew != 'n') {
                    printf("Please choose either Y or N");
                    goto YN1;
                  }
                }
              }
            }
            break;
        case 2:
            printf("\nYou have chosen *3 Resistors*");
            {
              {
                printf("\nEnter Value of Each Resistor (in Ohm)  : \n");
                for (i = 0; i < 3; i++) {
                  printf("\nR%d : ", i + 1);
                  scanf("%f", &r[i]);
                  rone3 = rone2;
                  rone2 = rone1;
                  rone1 = r[0];
                  rtwo3 = rtwo2;
                  rtwo2 = rtwo1;
                  rtwo1 = r[1];
                  rthree3 = rthree2;
                  rthree2 = rthree1;
                  rthree1 = r[2];
                }
                for (i = 0; i < 3; i++) {
                  RsS = RsS + r[i];
                }
                printf("\nEquivalent Series Resistance = %.4f Ohm", RsS);
                Rs3 = Rs2;
                Rs2 = Rs1;
                Rs1 = RsS;
                getch();
                system("CLS");
              YN2:
                {
                  printf("\nDo you want to calculate a new one?\n");
                  printf("\nPress Y for *Yes* and *N* for No (End Program after showing summary) \n");
                  fflush(stdin);
                  scanf("%c", &choicenew);
                  system("CLS");
                  if (choicenew == 'Y' || choicenew == 'y') {
                    goto select;
                  } else if (choicenew == 'N' || choicenew == 'n') {
                    goto summary;
                    break;
                  } else {
                    printf("Please choose either Y or N");
                    goto YN2;
                  }
                }
              }
            }
            break;
        default:
            printf("Sorry you are only allowed to choose either 2 or 3 resistors\n");
            goto start3;
            break;
          }
        }
        break;
    case 2:
        printf("You have chosen *Parallel Circuit*");
        float RsP = 0, invRsP = 0;
        {
          printf("\nEnter the number of Resistors in your circuit:\n ");
          printf("\nPress 1 for 2 Resistors \nPress 2 for 3 Resistors \n ");
          int choiceRs;
        start4:
          scanf("%d", &choiceRs);
          choiceRs3 = choiceRs2;
          choiceRs2 = choiceRs1;
          choiceRs1 = choiceRs;
          switch (choiceRs)
          {
          case 1:
            printf("\nYou have chosen *2 Resistors*");
            /*float r[10]; */
            {
              {
                printf("\nEnter Value of Each Resistor (in Ohm)  : n");
                for (i = 0; i < 2; i++) {
                  printf("\n R%d : ", i + 1);
                  scanf("%f", &r[i]);
                  rone3 = rone2;
                  rone2 = rone1;
                  rone1 = r[0];
                  rtwo3 = rtwo2;
                  rtwo2 = rtwo1;
                  rtwo1 = r[1];
                  rthree3 = rthree2;
                  rthree2 = rthree1;
                  rthree1 = r[2];
                }
                for (i = 0; i < 2; i++) {
                  invRsP += (1.0 / r[i]);
                }
                RsP = (1.0 / invRsP);
              }
              printf("\nEquivalent Parallel Resistance = %.4f Ohm", RsP);
              Rs3 = Rs2;
              Rs2 = Rs1;
              Rs1 = RsP;
              getch();
              system("CLS");
            YN3:
              {
                printf("\nDo you want to calculate a new one?\n");
                printf("\nPress Y for *Yes* and N for *No* (End Program after showing summary)\n");
                fflush(stdin);
                scanf("%c", &choicenew);
                system("CLS");
                if (choicenew == 'Y' || choicenew == 'y') {
                  goto select;
                } else if (choicenew == 'N' || choicenew == 'n') {
                  goto summary;
                  break;
                } else {
                  printf("Please choose either Y or N");
                  goto YN3;
                }
              }
            }
            break;
          case 2:
            printf("\nYou have chosen *3 Resistors*");
            {
              {
                printf("\nEnter Value of Each Resistor (in Ohm) : \n");
                for (i = 0; i < 3; i++) {
                  printf("\n R%d : ", i + 1);
                  scanf("%f", &r[i]);
                  rone3 = rone2;
                  rone2 = rone1;
                  rone1 = r[0];
                  rtwo3 = rtwo2;
                  rtwo2 = rtwo1;
                  rtwo1 = r[1];
                  rthree3 = rthree2;
                  rthree2 = rthree1;
                  rthree1 = r[2];
                }
                for (i = 0; i < 3; i++) {
                  invRsP += (1.0 / r[i]);
                }
                RsP = (1.0 / invRsP);
              }
              printf("\nEquivalent Parallel Resistance = %.4f Ohm", RsP);
              Rs3 = Rs2;
              Rs2 = Rs1;
              Rs1 = RsP;
              getch();
              system("CLS");
            YN4:
              {
                printf("Do you want to calculate a new one?");
                printf("\nPress Y for *Yes* and N for *No* (End Program after showing summary)\n");
                fflush(stdin);
                scanf("%c", &choicenew);
                system("CLS");
                if (choicenew == 'Y' || choicenew == 'y') {
                  goto select;
                } else if (choicenew == 'N' || choicenew == 'n') {
                  goto summary;
                  break;
                } else {
                  printf("Please choose either Y or N");
                  goto YN4;
                }
              }
            }
            break;
          default:
            printf("Sorry you are only allowed to choose either 2 or 3 resistors\n");
            goto start4;
            break;
          }
        }
    default:
        printf("Sorry please choose either 1 or 2 \n");
        goto start2;
        break;
      }
    summary:
      system("COLOR CF");
      printf("------------------------------------------------------");
      printf("\nTake Note :");
      printf("\n\nCircuit type:\n1 = Series Circuit &\n2 = Parallel Circuit\n\n");
      printf("\nCalculation 1 is the latest while Calculation 3 was the earliest");
      printf("\n------------------------------------------------------------\n");
      printf
          ("\nCalculation 1 : Equivalent Resistance = %.4f Ohm You chose Circuit type %.f  and %.f Resistors  \nR1=%.f, R2=%.f, R3=%.f\n",
           Rs1, choiceSP1, choiceRs1 + 1, rone1, rtwo1, rthree1);
      printf
          ("\nCalculation 2 : Equivalent Resistance = %.4f Ohm You chose Circuit type %.f  and %.f Resistors  \nR1=%.f, R2=%.f, R3=%.f\n",
           Rs2, choiceSP2, choiceRs2 + 1, rone2, rtwo2, rthree2);
      printf
          ("\nCalculation 3 : Equivalent Resistance = %.4f Ohm You chose Circuit type %.f  and %.f Resistors  \nR1=%.f, R2=%.f, R3=%.f\n",
           Rs3, choiceSP3, choiceRs3 + 1, rone3, rtwo3, rthree3);
      printf("\n**************************************************************\n");
      printf("                                           THANK YOU!!!!             ");
      printf("************************************************************");
    }
  }
}

You need to learn to:
* properly indent your code;
* stop using goto (use while and for instead)
* use arrays
* use functions
* don't flush(stdin)