Rand # Game - Segmentation fault (core dumped) Error - More to Follow(maybe)

[Cameron Taylor]

Ok, so doing an assignment for a random number game where you guess and it says too high or too low until you get it right or run out of tries. Here is what I got so far:

//Cameron Taylor

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

int main(){

    srand(time(0));
    int number = rand()%100+1;;
    int guess, numberGuess;

    printf("Im thinking of a number between 1-100. You only have 7 chances, so choose carefully.");
    printf("Now, Take a Guess: ");
    scanf("%d", guess); 

while(guess!=number && numberGuess<=7){        

    if(guess>number)
    {
        printf("Too high,Guess again: ");
        scanf("%d", guess);
        numberGuess++;
    }
    if(guess<number)
    {
        printf("Too low,Guess again: ");
        scanf("%d", guess);
        numberGuess++;
    }
    if(guess==number)
    {
        printf("Congratulations!, You guessed the number");
    } 
}
return 0;}

Getting "Segmentation fault (core dumped)" after inputting the first number, but it compiles correctly.

_________________________________________________

I later have to add "Do you want to play again (y/n)", so I will use this post to continue that later.

[laserlight]

Compile at a higher warning level. Does the compiler warn you about something?

[Cameron Taylor]

Compile at a higher warning level. Does the compiler warn you about something?

I just use:

make Exercise6

It spits out:

cc Exercise6.c -o Exercise6



How do I increase the level to make it show more?

[laserlight]

The options to increase warning level depends on the compiler, but I'm not sure what compiler is cc. You probably can run:

cc --version

to find out. After that, find the documentation for that compiler, searching online if you must. If you cannot find it, then tell us what is it.

Anyway, take a closer look at this line:

scanf("%d", guess);

[Cameron Taylor]

The options to increase warning level depends on the compiler, but I'm not sure what compiler is cc. You probably can run:

cc --version

to find out. After that, find the documentation for that compiler, searching online if you must. If you cannot find it, then tell us what is it.

It is just GCC - cc (GCC) 4.7.2 20121109 (Red Hat 4.7.2-8)

I did -Wall, but I couldn't make heads or tails of what the info it gave me meant.

Anyway, take a closer look at this line:

scanf("%d", guess);

Bah... "&" was missing. That made it work. Thanks.

[whiteflags]

Ok so here's an example of the warning you fixed.

bla.c:13:5: warning: format '%d' expects argument of type 'int *', but argument
2 has type 'int' [-Wformat]

gcc will check printf and friends' arguments to make sure that they're right. Key things to comprehend are what gcc thought the problem format conversion was (%d), the type it expects (int * - as generated by &guess), what you actually passed in (int - guess), and which argument is exactly the problem if you counted them. It just takes a bit of reading comprehension.

[Cameron Taylor]

Ok so here's an example of the warning you fixed.


gcc will check printf and friends' arguments to make sure that they're right. Key things to comprehend are what gcc thought the problem format conversion was (%d), the type it expects (int * - as generated by &guess), what you actually passed in (int - guess), and which argument is exactly the problem if you counted them. It just takes a bit of reading comprehension.

This is what my compiler said when I compiled with -Wall:

Exercise6: In function `_fini':
(.fini+0x0): multiple definition of `_fini'
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../lib64/crti.o:(.fini+0x0): first defined here
Exercise6: In function `data_start':
(.data+0x0): multiple definition of `__data_start'
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../lib64/crt1.o:(.data+0x0): first defined here
Exercise6:(.rodata+0x8): multiple definition of `__dso_handle'
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/crtbegin.o:(.rodata+0x0): first defined here
Exercise6:(.rodata+0x0): multiple definition of `_IO_stdin_used'
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../lib64/crt1.o:(.rodata.cst4+0x0): first defined here
Exercise6: In function `_start':
(.text+0x0): multiple definition of `_start'
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../lib64/crt1.o:(.text+0x0): first defined here
Exercise6: In function `_init':
(.init+0x0): multiple definition of `_init'
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../lib64/crti.o:(.init+0x0): first defined here
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/crtend.o:(.tm_clone_table+0x0): multiple definition of `__TMC_END__'
Exercise6:(.data+0x8): first defined here
/usr/bin/ld: error in Exercise6(.eh_frame); no .eh_frame_hdr table will be created.
collect2: error: ld returned 1 exit status

[Cameron Taylor]

Ok, thanks to the help i got the game to work, but I also need to make it ask if the user wants to play again. This is what I have so far in a "Do While" loop.

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

int main(){

    srand(time(0));
    int number = rand()%100+1;
    int guess, numberGuess;
    char playagain='y';

    printf("Im thinking of a number between 1-100. You only have 8 chances, so choose carefully.");
    printf("Now, Take a Guess: ");
    scanf("%d", &guess); 
    numberGuess++;

while (playagain != 'n'){

    while(guess!=number && numberGuess<=7){        

        if(guess>number)
        {
            printf("Too high,Guess again: ");
            scanf("%d", &guess);
            numberGuess++;
        }
        if(guess<number)
        {
            printf("Too low,Guess again: ");
            scanf("%d", &guess);
            numberGuess++;
        }
        if(guess==number)
        {
            printf("Congratulations!, You guessed the number");
        } 
    }

    do {
        printf("Would you like to play again?");
        scanf("%c", &playagain);
    }
        while (playagain !='y' && playagain != 'n');
}    
return 0;}

Though, this line:

printf("Would you like to play again?");

is repeating twice back to back and when I enter in "y" it doesn't re-execute the program. Though when I type in 'n' it does exit the program.

[whiteflags]

I would suggest:

scanf(" %c", &playagain);

You have a ton of left over newlines in the input that are causing scanf to behave weird. %c is different in that it does not ignore white space in the input.

I I would factor out the call to scanf to read the guess in to some place below all the ifs, too. No need to repeat it in two places.

[Cameron Taylor]

I would suggest:

scanf(" %c", &playagain);

You have a ton of left over newlines in the input that are causing scanf to behave weird. %c is different in that it does not ignore white space in the input.

I I would factor out the call to scanf to read the guess in to some place below all the ifs, too. No need to repeat it in two places.

I will have to look into that, but do you know why it doesn't repeat the program when I put 'y' in on the "Would you like to play again?" line?

[vart]

because it reads the '\n' left after the previous scanf

most scanf formats will skip whitespaces before startign parsing the input stream. Not so for %c format - it starts parsing input stream where the previous scanf stopped.

[Cameron Taylor]

because it reads the '\n' left after the previous scanf

most scanf formats will skip whitespaces before startign parsing the input stream. Not so for %c format - it starts parsing input stream where the previous scanf stopped.

I think I got it with the " %c" help, but now once my program repeats it just allows the first guess before going back to the "do" line. Like so:

commiedic@localhost Project1$ ./Exercise6
Im thinking of a number between 1-100. You only have 8 chances, so choose carefully.Now, Take a Guess: 1
Too low,Guess again: 1
Too low,Guess again: 1
Too low,Guess again: 1
Too low,Guess again: 1
Too low,Guess again: 1
Too low,Guess again: 1
Too low,Guess again: 1
Would you like to play again? (y/n)y
Im thinking of a number between 1-100. You only have 8 chances, so choose carefully.Now, Take a Guess: 1
Would you like to play again? (y/n)n

UPDATED CODE:

//Cameron Taylor

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

int main(){

    srand(time(0));
    int guess, numberGuess;
    char playagain;



while (playagain != 'n'){

    int number = rand()%100+1;;
    printf("Im thinking of a number between 1-100. You only have 8 chances, so choose carefully.");
    printf("Now, Take a Guess: ");
    scanf(" %d", &guess); 
    numberGuess++;

    while(guess!=number && numberGuess<=7){        

        if(guess>number)
        {
            printf("Too high,Guess again: ");
            scanf("%d", &guess);
            numberGuess++;
        }
        if(guess<number)
        {
            printf("Too low,Guess again: ");
            scanf("%d", &guess);
            numberGuess++;
        }
        if(guess==number)
        {
            printf("Congratulations!, You guessed the number");
        } 
    }

    do {
        printf("Would you like to play again? (y/n)");
        scanf(" %c", &playagain);
    }
        while (playagain !='y' && playagain != 'n');
}    
return 0;}

[vart]

What do you think a value of numberGuess will be when you take your guess after pressing y?

[Cameron Taylor]

What do you think a value of numberGuess will be when you take your guess after pressing y?

OHHHHHHH I forgot to reset the count...

Added numberGuess = 0 above int number = rand()%100+1;

Thanks so much. 5 min late, but hopefully my instructor will still accept it.