I have doubts on how to define a string inside a switch in C, without having to do a table of constants for this.
The variable name_lanche is of type char, but this is the number of characters defined, so I am using it as a string. I need the variable to be empty before the switch and after passing the switch if the case is true it would get the designated value.
There are 3 ways to solve the problem without using a constant table.
1) Char pointer to string constant:
#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 memory allocation:
#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 have helped!
Not possible. Or you should use other language constructs ( if strcmp() ) or create an auxiliary table to handle this (a hash table is often used).
If you can use constants in place of strings , it is better.