Thread: Problem with a guess game using a while and do-while loops

Hello! I am a beginner in C programming. I was trying to write a program which asks a user to guess a secret number which is created by rand() function.
At this stage the program should tell how many digits of the nuber given by user coincide with digits of the secret number.
The problem is that even if the user guesses n digits, the program gives a number <n.
Example:

Enter a new number:3546
6305
number of guessed digits is 2

(In the middle is the secret number.)

Code:

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


int main(){
    setvbuf(stdout,NULL,_IONBF,0);


    int n=10000;
    srand(time(NULL));
    int r=rand()%n;


    int d1,d2,d3,d4;


    d1=r/1000;
    d2=(r-d1*1000)/100;
    d3=(r-d1*1000-d2*100)/10;
    d4=r-d1*1000-d2*100-d3*10;


    printf("%d,%d,%d,%d\n",d1,d2,d3,d4);


    char c;


    if(d1!=d2&&d1!=d3&&d1!=d4&&d2!=d3&&d2!=d4&&d3!=d4){


     printf("Enter a number:");
     scanf("%c",&c);


     while(c!='\n'){
     int k=0;


     do{
      c=getchar();
      int digit=c-48;


       if(digit==d1){
        ++k;
       }
       else if(digit==d2){
        ++k;
        }
       else if(digit==d3){
        ++k;
       }
       else if(digit==d4){
        ++k;
       }


      }while(c!='\n');




     printf("%i\n",r);
     printf("number of guessed digits is %i\n\n",k);


     printf("Enter a new number:");
     scanf("%c",&c);
     }
    }


    return 0;
}

Thanks for help in advance!

Hi

Lines 34 and 70, why are you reading that character? Remove those lines.

If the number is 7894 and if user enters 7894, 1st character goes to scanf and getchar reads only 894 so output is 3.
If user enters x7894, 'x' goes to scanf and getchar reads 7894 so output is 4.
Note: if user enters 7777 output will be 4. Find a way to overcome that.

Are you trying to terminate program if user enters only '\n'?
I think that it's better to use some other character.
You can edit your code e. g. like this:

Code:

printf("Enter a number:");
while(true){
    int k=0;
    do {  
        c = getchar();
        if (c == '-') return 0;
        ...
    }
    ...
}

What do you think about implementing this logic into your game:

while true (i. e. while user doesn't enter '-')
--- generate random number
--- while user doesn't guess number ask him for input

You're welcome.

(without duplicating digits)

Very clever

and question mark

You have misunderstood me Change that line (54) back to while(c!='\n')
I suggested you to make an infinite loop and that special character (e. g. '?') was supposed to be entered by user if he wants to quit.

I have implemented those things in my version of your game, but I'll not post that until you finish your game.

Code:

while (true) { // c variable is uninitialised before this loop so it's not a good idea to use it in a condition... better idea is to make an infinite loop
    int k=0;
    do{
        c=getchar();
        if (c == '?') return 0; // if user enters '?' then game over
        int digit=c-48;
        if (digit == d1){
            ++k;
        }
        else if(digit==d2){
            ++k;
        }
        else if(digit==d3){
            ++k;
        }
        else if(digit==d4){
            ++k;
        }
   }while(c!='\n');
}

Btw what if user enters 0123456789?