CODEWITHSUNDEEP
c
Anne
Anne

Reputation: 3

Quit Option in C

I know this is a really silly piece of code and it's only for me to try and get my head around things... I think I've done okay, (apart from not properly indenting)

But I'm struggling with giving the user the option to quit the program using the 'Q' Character, but can't seem to get it right?

Can anybody please help.. 

#include <stdio.h>
#define YEAR 2015

int main()
{
    int yearBorn, age, ageLimit,years;
    char quit = 'Q';

    ageLimit=16;

    do // The program will continue running until the user enters an age greater than 16 or presses the 'Q' character
       // to quit the program
    {        
        printf("\nPlease Enter The Year You Were Born: ");
        scanf(" %d", &yearBorn);

        age= YEAR-yearBorn;
        years=ageLimit-age;

        if (yearBorn==YEAR) //This IF statement will run if the user enters the current year!
        {
            printf("Please double check your entry as it seems ");
            printf("that you havent been born yet?");

        }
        else if (age<=ageLimit) //If the users age is less than 16 program prints the following messages
        {
            printf("\nYou are too young to play the Lottery!\n");
            printf("you have to wait %d year%s before you can play!\n\n",years,(years!=1) ? "s" : " ");

            printf("You are %d\n",age);    
        }    
    }while (years>=1);

    age = YEAR-yearBorn;    
    printf("You're old enough.. for heavens sake you are %d years old \n", age);

    return 0;
}

Upvotes: 0

Views: 230

Answers (3)

user3629249
user3629249

Reputation: 16540

the following is one way to handle this application

notice the inclusion of error checking
notice the inclusion of a proper user prompt 
notice the method for checking of the user entered 'Q'
notice the method for exiting the application
notice that 'age', once calculated does not need to be recalculated
    when exiting program
this algorithm can fail when the year born is 16 years ago
    as it would then depend on the birth month/day compared to today
It would be a good idea to check the converted yearBorn for validity
    as a atoi() failure would result in yearBorn being 0;


#include <stdio.h>
#include <stdlib.h>  // exit and EXIT_FAILURE

#define YEAR      (2015)
#define AGE_LIMIT (16)
#define QUIT      'Q'

int main()
{
    int  yearBorn;
    int  age;
    int  years = 1;

    char buffer[20];




    do // The program will continue running until the user enters an age greater than 16 or presses the 'Q' character
       // to quit the program
    {
        printf("\nPlease Enter The Year You Were Born or 'Q' to quit: ");
        if( NULL == fgets( buffer, sizeof buffer, stdin ) )
        { // then fgets failed
            perror( "fgets for birth year failed" );
            exit( EXIT_FAILURE );
        }

        // implied else, fgets successful

        if( QUIT == buffer[0] ) {break;}

        yearBorn = atoi(buffer);

        age= YEAR-yearBorn;
        years=AGE_LIMIT-age;

        if (yearBorn==YEAR) //This IF statement will run if the user enters the current year!
        {
            printf("Please double check your entry as it seems ");
            printf("that you havent been born yet?");

        }

        else if (age<AGE_LIMIT) //If the users age is less than 16 program prints the following messages
        {
            printf("\nYou are too young to play the Lottery!\n");
            printf("you have to wait %d year%s before you can play!\n\n",years,(years!=1) ? "s" : " ");

            printf("You are %d\n",age);
        }  // end if

    }while (years>=1);

    if( years <= 0 )
    {
        printf("You're old enough.. for heavens sake you are %d years old \n", age);
    }

    return 0;
} // end function: main

Upvotes: 0

DWilches
DWilches

Reputation: 23015

For that, don't use:

scanf("%d", &yearBorn)

use instead:

char someString[100];
scanf("%99s", someString)

and then check if someString is "Q" (using stricmp). If it is not, then you can use atoi to convert it to a number.

Upvotes: 1

mcleod_ideafix
mcleod_ideafix

Reputation: 11428

Just declare an opt variable of type char and add this just before the } while (years>1); line:

printf ("Press %c and ENTER to quit, or just ENTER to repeat: ", quit);
do
  opt = getchar();
while (opt!=quit && opt!='\n');
if (opt==quit)
  break;

To avoid executing always the last printf, enclose it in an if statement

if (opt!=quit)
{
    age = YEAR-yearBorn;    
    printf("You're old enough.. for heavens sake you are %d years old \n", age);
}

Upvotes: 1

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