Determining a string within a C switch

Question

I have doubts about how to define a string within a switch in C, without having to make a table of constants for this.

The variable nome_lanche is the type char, but this with the number of characters set, so I’m using as a string.

I need the variable to be empty before the switch and after passing the switch if the case is true it will receive the designated value.

Answer 1

Not possible. Or use other language construction (if strcmp()) or create an auxiliary table to take care of it (a table hash is usually used).

Constants may be used instead of strings, better.

Answer 2

Here are 3 ways to solve the problem without using a table of constants.

1) Char pointer for constant string:

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

int main( int argc, char * argv[] )
{
    char * nome_lanche = NULL;
    int preco_lanche = 0;
    int cod_lanche = atoi( argv[1] );

    switch( cod_lanche )
    {
        case 0:
            nome_lanche = "macarrao";
            preco_lanche = 10;
            break;

        case 100:
            nome_lanche = "hamburger";
            preco_lanche = 5;
            break;

        default:
            nome_lanche = "invalido";
            preco_lanche = -1;
            break;
    }

    printf("Codigo: %d\n", cod_lanche );
    printf("Nome: %s\n", nome_lanche );
    printf("Preco: %d\n", preco_lanche );

    return 0;
}

/* fim-de-arquivo */

2) Static memory allocation (chars vector):

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

#define NOME_MAX_TAM  (100)

int main( int argc, char * argv[] )
{
    char nome_lanche[ NOME_MAX_TAM + 1 ] = {0};
    int preco_lanche = 0;
    int cod_lanche = atoi(argv[1]);

    switch( cod_lanche )
    {
        case 0:
            strcpy( nome_lanche, "macarrao" );
            preco_lanche = 10;
            break;

        case 100:
            strcpy( nome_lanche, "hamburger");
            preco_lanche = 5;
            break;

        default:
            strcpy( nome_lanche, "codigo invalido" );
            preco_lanche = -1;
            break;
    }

    printf("Codigo: %d\n", cod_lanche );
    printf("Nome: %s\n", nome_lanche );
    printf("Preco: %d\n", preco_lanche );

    return 0;
}

/* fim-de-arquivo */

3) Dynamic allocation of memory:

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

int main( int argc, char * argv[] )
{
    char * nome_lanche = NULL;
    int preco_lanche = 0;
    int cod_lanche = atoi(argv[1]);

    switch( cod_lanche )
    {
        case 0:
            nome_lanche = strdup("macarrao");
            preco_lanche = 10;
            break;

        case 100:
            nome_lanche = strdup("hamburger");
            preco_lanche = 5;
            break;

        default:
            nome_lanche = strdup("codigo invalido");
            preco_lanche = -1;
            break;
    }

    printf("Codigo: %d\n", cod_lanche );
    printf("Nome: %s\n", nome_lanche );
    printf("Preco: %d\n", preco_lanche );

    free( nome_lanche );

    return 0;
}

/* fim-de-arquivo */

I hope I’ve helped!