Thread: For Loop Disaster

  1. #1
    Registered User
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    Angry For Loop Disaster

    Currently trying how to use the For loop but I知 not having much luck. Just trying to print a name ten times but I reckon I知 doing something wrong? Your help would be much appreciate as i am getting very frustrated!

    Code:
    #include<conio.h>
    #include<stdio.h>
    #include<stdlib.h>
    
    char name[25];
    void input_name()
    {
         printf("please enter your name.");
         scanf("s%",&name);
    }
    void process()
    {
    for (name; <10; name+1)
        printf("Your name is %s/n",name);
    }
    
    int main()
    {
        input_name();
        process();
        getch();
        return 1;
    }

  2. #2
    Resu Deretsiger Nightowl's Avatar
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    Code:
    void process()
    {
    for (name; <10; name+1)
        printf("Your name is %s/n",name);
    }
    That section has a few bugs in it . . .

    First off . . . for (name; <10; name+1) is incorrect. Try for (; name<10; name++) instead.

    Now, printf("Your name is %s/n",name); again, has a bit of a problem. I'll let you find it, but one tip: /.

    Also, what's that return 1; doing there?

    Remember that bash is the opposite of C: 0 is true, successful, and !0 is false, unsuccessful. Just to confuse you some more. :P

    EDIT: A-whoops-a-dasies. Didn't notice the double post. My apologies.
    Last edited by Nightowl; 03-22-2009 at 09:03 PM.
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  3. #3
    Hurry Slowly vart's Avatar
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    scanf("s%",&name); - & should be removed.

    Using global variables is not recomanded - pass parameters by pointer

    to prevent buffer overrun - add width modifier to the format

    Code:
    char name[25];
    scanf("%24s", name);
    All problems in computer science can be solved by another level of indirection,
    except for the problem of too many layers of indirection.
    David J. Wheeler

  4. #4
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    Code:
    void process()
    {
        int i;
        for (i = 0; i<10; i++)
            printf("Your name is %s\n",name);
    }
    Okay, so what did I do here? First of all you shouldn't be checking the name variable against an integer condition. You will most likely get a compilation error as it is a type mismatch. So we replace that condition with a different one, we create an integer value and test that value.

    Another tip: refrain from using scanf(), it is particularly unsafe, try entering in a string that is more then 25 characters long and you will see. A safer alternative is fgets() (which I believe is deprecated now) or even perhaps getline(&buffer, &length, stdin); Don't use fixed size arrays on the second one because it will spit out an error if you enter a string more then the array size.

  5. #5
    Hurry Slowly vart's Avatar
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    Quote Originally Posted by hawaiian robots View Post
    Another tip: refrain from using scanf(), it is particularly unsafe,
    you should learn to use it correctly

    fgets() (which I believe is deprecated now)
    it is not

    or even perhaps getline(&buffer, &length, stdin);
    I do not think there is standard function like this
    All problems in computer science can be solved by another level of indirection,
    except for the problem of too many layers of indirection.
    David J. Wheeler

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