Thread: C Programming For The Absoloute Beginner Chapter 3 Challenge 2 Query

I've been working on this program for a good couple of weeks between my work hours.

The challenge in the book was:
Build a number guessing game that uses input validation (isdigit function) to verify that the user has entered a digit and not a non-digit (letter).

The following is the best I could come up with.

You'll notice that I ask the user to input their guess twice, once to assign to an integer and once to a character because I had no idea how to effectively convert the character to an integer.

This is the first proper game I have made with C so please feel free to point out any rookie errors :>

Any suggestions as to how to improve the code from here?

Cheers.

Code:

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

int main()

{
    int iRandomNum = 0;
    srand(time(NULL));
    char cResponse = '\0';
    int dResponse = 0;

iRandomNum = (rand()%10)+1;

    printf("iRandomNum= %d\n",iRandomNum);
    printf("please enter a digit\n");

    scanf("%c",&cResponse);
    printf("One more time?\n");
    scanf("%d",&dResponse);
    printf("cResponse= %c\n",cResponse);

if (isdigit (cResponse)==0)
    printf("letter was inserted, please enter a number next time\n");
else
    printf("iRandomNum= %d, this is a digit.\n",iRandomNum,", \n");


if (dResponse == iRandomNum)
    printf(" well done!");

else {
        printf("you lose\n");
        printf("You guessed cResponse= %c\n",cResponse);
        printf("You should have guessed %d",iRandomNum);}
}

Those are just artefacts that didn't get picked up in debugging.
Now that I have deleted them, it looks like this:
printf("iRandomNum= %d, this is a digit.\n", iRandomNum);
I use it to return the value f iRandomNum for debugging.

Currently trying to integrate atoi in so that I don't need to ask the user to input their answer twice.
Already made the program crash so that is proving fun to solve.

Code:

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

int main(void)

{
    int iRandomNum = 0;
    srand(time(NULL));
    char cResponse = '\0';
    int dResponse = 0;

iRandomNum = (rand()%10)+1;

    printf("iRandomNum= %d\n",iRandomNum);
    printf("please enter a digit\n");

    scanf("%c",&cResponse);
    printf("cResponse= %c\n",cResponse);


if (isdigit (cResponse)==0)
    printf("letter was inserted, please enter a number next time\n");
else
    printf("iRandomNum= %d, this is a digit.\n", iRandomNum);

dResponse = atoi(cResponse);
printf("%d",dResponse);

if (dResponse == iRandomNum)
    printf(" well done!");

else {
        printf("you lose\n");
        printf("You guessed cResponse= %c\n",cResponse);
        printf("You should have guessed %d",iRandomNum);}
}

Originally Posted by Dekuben

Currently trying to integrate atoi in so that I don't need to ask the user to input their answer twice.
Already made the program crash so that is proving fun to solve.

Like a hint?

Look up scanf() in your C library documentation. It will almost certainly have more information than your textbook... pay special attention to it's return value.

Now with that in mind... think about doing your inputs directly into an integer.

A little testing and you might be surprised how easy it is...