Thread: How to go back from switch menu

I want to make a menu that classifies animals into insects, birds, mammals and fishes with specific characteristics for each of these (using composite variables). I thought I'd use a nested switch case(one switch for the category of the animals and another switch for each category to perform the actions). The problem is, after I've entered a new entry for instance, I wanna have the option to go back and pick another action or even go back and pick another category. How can I do that? I tried with a do-while but I'm just getting an endless loop.

Code:

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



typedef struct{
    unsigned int noLegs, lifeSpan;
    char *name;
}insect;




typedef struct{
    float speed, length;
    char *habits, *name;
}bird;




typedef struct{
    float weight, height;
    char *food, *name;
}mammal;




typedef struct{
    float weight, depth, salt;
    char *name;
}fish;




int main(int argc, char **argv)
{
    char choice, action;
    insect *i = (insect *)malloc(sizeof(insect));


    if(!i)
    {
        printf("Failed to allocate memory.\n");
        return -1;
    }


    printf("Please choose a category:\n");
    printf("1. Insects\n2. Birds\n3. Mammals\n4. Fishes\n");
    scanf("%c", &choice);


    switch(choice)
    {
        case '1':
            printf("You've chosen: Insects\n");
            printf("Please choose an action:\n");
            printf("a. Add entry\nb. Delete entry\nc. Replace entry\nd. Lookup entries\ne. Back\n");
            scanf(" %c", &action);


            switch(action)
            {
                case 'a':
                    printf("What entry would you like to add?\n");
                    i->name = (char *)malloc(sizeof(char));
                    scanf("%s", i->name);
                    printf("How many legs does a %s have?\n", i->name);
                    scanf("%u", &(i->noLegs));
                    printf("What is the lifespan of a %s?\n", i->name);
                    scanf("%u", &(i->lifeSpan));
                    break;
                case 'b':
                    printf("Which entry would you like to delete?\n");
                    break;
                case 'c':
                    printf("Which entry would you like to replace?\n");
                    break;
                case 'd':
                    printf("The current entries:\n");
                    break;
                case 'e':
                    printf("Back\n");
                    break;
                default:
                    printf("Invalid action.\n");
            }
            break;
        case '2':
            printf("You've chosen: Birds\n");
            printf("Please choose an action:\n");
            printf("a. Add entry\nb. Delete entry\nc. Replace entry\nd. Lookup entries\n");
            scanf(" %c", &action);
            switch(action)
            {
                case 'a':
                    printf("What entry would you like to add?\n");
                    break;
                case 'b':
                    printf("Which entry would you like to delete?\n");
                    break;
                case 'c':
                    printf("Which entry would you like to replace?\n");
                    break;
                case 'd':
                    printf("The current entries:\n");
                    break;
                default:
                    printf("Invalid action.\n");
            }
            break;
        case '3':
            printf("You've chosen: Mammals\n");
            printf("Please choose an action:\n");
            printf("a. Add entry\nb. Delete entry\nc. Replace entry\nd. Lookup entries\n");
            scanf(" %c", &action);
            switch(action)
            {
                case 'a':
                    printf("What entry would you like to add?\n");
                    break;
                case 'b':
                    printf("Which entry would you like to delete?\n");
                    break;
                case 'c':
                    printf("Which entry would you like to replace?\n");
                    break;
                case 'd':
                    printf("The current entries:\n");
                    break;
                default:
                    printf("Invalid action.\n");
            }
            break;
        case '4':
            printf("You've chosen: Fishes\n");
            printf("Please choose an action:\n");
            printf("a. Add entry\nb. Delete entry\nc. Replace entry\nd. Lookup entries\n");
            scanf(" %c", &action);
            switch(action)
            {
                case 'a':
                    printf("What entry would you like to add?\n");
                    break;
                case 'b':
                    printf("Which entry would you like to delete?\n");
                    break;
                case 'c':
                    printf("Which entry would you like to replace?\n");
                    break;
                case 'd':
                    printf("The current entries:\n");
                    break;
                default:
                    printf("Invalid action.\n");
            }
            break;
        default:
            printf("Invalid choice.\n");
    }
    return 0;
}