Its possible use "if else" inside "case"?

Question

#include<stdio.h>

#include<stdlib.h>

#include<ctype.h>

int main ()

{

int comic,D,M,F;

int flash=3.55,superman=4.99,wonderwoman=2.85,batman=4.99,greenlantern=3.80;

int hulk=3.55,ironman=4.85,capitanamerica=4.15,capitanmarvel=2.75,avengers=4.99;

char op;

do

{

printf("\nMENU\n\nDC - DC Comics\nM - Marvel Comics");

        printf("\nC close sale\nOPTION:");

        scanf("%s",op);

        op = toupper(op);

        char op;

        switch (op)

        {

            case 'D':

                       if(comic == 1)

                           printf("\nYou bought a comic of flash");

                        else

                            if(comic == 2)

                                printf("\nYou bought a comic of superman");

                            else

                                if (comic == 3)

                                     printf("\nYou bought a comic of wonder woman");

                                else

                                    if (comic == 4)

                                         printf("\nYou bought a comic of batman");

                                    else

                                        if (comic == 5)

                                             printf("\nYou bought a comic of green lantern");

                                        else

                                            printf("\nNone Exist");

                                            break;

            case 'M':

                       if(comic==6)

                           printf("\nYou bought a comic of hulk");

                        else

                            if(comic==7)

                                printf("\nYou bought a comic of iron man");

                            else

                                if(comic==8)

                                    printf("\nYou bought a comic of capitan america");

                                else

                                    if(comic==9)

                                        printf("\nYou bought a comic of capitan marvel");

                                    else

                                        if(comic==10)

                                            printf("\nYou bought a comic of avengers");

                                        else

                                            printf("\nNone Exist");

                                            break;

            case 'F':

                       printf("\nGoing Out");

                       break;

            default:   

                       printf("\nNONEXISTENT OPTION");

        }

        fgetc(stdin);

}

while(op!='finish');

system("pause");

return 0;

}

Answer 1

---

printf("\nMENU\n\nDC - DC Comics\nM - Marvel Comics");

        printf("\nC close sale\nOPTION:");

        scanf("%s",op);

---

should be

---

printf("\nMENU\n\nDC - DC Comics\nM - Marvel Comics");

        printf("\nC close sale\nOPTION:");

        scanf("%c",&op);

---

Original code has new var "op"  before the switch ,which over-rides the input from user & is un wanted.

       op = toupper(op);

        char op;

        switch (op

Post that not sure where values of "comic" was read .. after which it matches in the inner case statements

Answer 2

Problems with the code

There are various issues with the code. Some of them have a warning too, when you compile. You just have to pay attention to them.

#include<stdio.h>
#include<stdlib.h>
#include<ctype.h>

int main() 
{
    int comic, D, M, F;
    int flash = 3.55, superman = 4.99, wonderwoman = 2.85, batman = 4.99, greenlantern = 3.80;
    int hulk = 3.55, ironman = 4.85, capitanamerica = 4.15, capitanmarvel = 2.75, avengers = 4.99;
    char op; // Problem #1: Definition of 'op'.
    do
    {
        printf ("\nMENU\n\nDC - DC Comics\nM - Marvel Comics");
        printf ("\nC close sale\nOPTION:");
        scanf ("%s", op); // Problem #2: reading string into char
        op = toupper (op);
        char op; // Problem #1: Redefinition of 'op'.
        switch (op)
        {
            case 'D':
                if (comic == 1)
                    printf ("\nYou bought a comic of flash");
                else
                    if (comic == 2)
                        printf ("\nYou bought a comic of superman");
                    else
                        if (comic == 3)
                            printf ("\nYou bought a comic of wonder woman");
                        else
                            if (comic == 4)
                                printf ("\nYou bought a comic of batman");
                            else
                                if (comic == 5)
                                    printf ("\nYou bought a comic of green lantern");
                                else
                                    printf ("\nNone Exist");
                break;

            case 'M':
                if (comic == 6)
                    printf ("\nYou bought a comic of hulk");
                else
                    if (comic == 7)
                        printf ("\nYou bought a comic of iron man");
                    else
                        if (comic == 8)
                            printf ("\nYou bought a comic of capitan america");
                        else
                            if (comic == 9)
                                printf ("\nYou bought a comic of capitan marvel");
                            else
                                if (comic == 10)
                                    printf ("\nYou bought a comic of avengers");
                                else
                                    printf ("\nNone Exist");
                break;

            case 'F':
                printf ("\nGoing Out");
                break;

            default:
                printf ("\nNONEXISTENT OPTION");
        }
        fgetc (stdin);
    } while (op != 'finish'); // Problem #3

    system ("pause");
    return 0;
}

Problem #1

The variable op has already been defined. Redefining it deletes its previous values. Fix: do not redefine it.

Problem #2

'op' is defined as a character, yet you read value to it as a C-string ("%s"). Also, scanf requires a memory pointer where it should write the read value, but you provide the variable (not the address of the variable, as it should be).

Fix: read just a single character from the input. (Alternatively, you could read a whole string, change the data type of op to char op[SOME_SIZE], where you pick the SOME_SIZE for your own buffer.)

scanf ("%c", &op);

Problem #3

You compare the character stored in op against the character 'f'. 'finish' is really just a single character 'f'. If you want to create a C-string, you have to do it in double quotes: "finish". Single quotes are for characters, that are really supposed to have a length of one, such as 'f'.

Furthermore. please remember that you made your op upper case so comparing it against a lower case 'f' will never yield true.

Fix: compare op against a single uppercase 'F' letter:

} while (op != 'F');

Problem #4

Well, the rest of the code is unfinished (e.g. comic is not set). Go ahead, and implement the rest.

Good luck! :)