Is there a function for ELSE to return on Switch?-CodePudding

Hello all i was wondering could someone help me , on the ELSE what im triying to do is to ask me again the correct number which will be 1 trough 7 and "forcing" the user to input the numbers of 1 trough 7.

#include <stdio.h>
#include <conio.h>

int main()
{
    int dia;
    printf("Escriba el número de día: \n");
    scanf("%d",&dia);
    if(dia>=1 && dia<=8)
        switch(dia)
        {
            case 1: printf("El día es Lunes");
                    break;
            case 2: printf("El día %d es Martes",dia);
                    break;
            case 3: printf("El día %d es Miércoles",dia);
                    break;
            case 4: printf("El día %d es Jueves",dia);
                    break;
            case 5: printf("El día %d es Viernes",dia);
                    break;
            case 6: printf("El día %d es Sábado",dia);
                    break;
            case 7: printf("El día %d es Domingo",dia);
                    break;
        }
    else {
        printf("ingrese número del 1-7");
    }
    getch();
    return 0;
}

CodePudding user response：

This is called default

for instance:

switch(c){
  case 0:
    printf("c is zero\n");
    break;
  case 1:
    printf("c is one\n");
    break;
  case 2: 
    printf("c is two\n");
    break;
  default:
    printf("c is not zero one or two\n");
    break;
}

CodePudding user response：

A way to do what you want to achieve is to keep the user in a loop until they enter the correct input. Like:

#include <stdio.h>
#include <conio.h>

int main()
{
    int dia;
    do{
        printf("Escriba el número de día: \n");
        scanf(" %d",&dia);
        if(dia<1||dia>8)
            printf("ingrese número del 1-7");
    }while(dia<1||dia>8);
    if(dia>=1 && dia<=8)
        switch(dia)
        {
            case 1: printf("El día es Lunes");
                    break;
            case 2: printf("El día %d es Martes",dia);
                    break;
            case 3: printf("El día %d es Miércoles",dia);
                    break;
            case 4: printf("El día %d es Jueves",dia);
                    break;
            case 5: printf("El día %d es Viernes",dia);
                    break;
            case 6: printf("El día %d es Sábado",dia);
                    break;
            case 7: printf("El día %d es Domingo",dia);
                    break;
        }
    getch();
    return 0;
}

CodePudding user response：

You can achieve your objective with far less code...

#include <stdio.h>

int main() {
    int dia = 0; // ALWAYS initialise variables
    char *str = NULL;

    printf( "Escriba el número de día: " );
    while( str == NULL ) {
        scanf( "%d", &dia );
        /* omitting test for failure */

        switch( dia ) {
            case 1: str = "Lunes"; break;
            case 2: str = "Martes"; break;
            case 3: str = "Miércoles"; break;
            case 4: str = "Jueves"; break;
            case 5: str = "Viernes"; break;
            case 6: str = "Sábado"; break;
            case 7: str = "Domingo"; break;
            // Catch any invalid input leaving str == NULL
            default:
                printf( "ingrese número del 1-7: " );
                break;
        }
    }
    printf( "El día %d es %s\n", dia, str );

    getch();

    return 0;
}

When the user enters a valid number, the pointer 'str' changes from NULL to the address of a weekday name. This causes the loop to exit, and the day number and name are printed.