For Loop Disaster

Chalmers86 · 03-22-2009, 04:54 PM

Currently trying how to use the For loop but I’m not having much luck. Just trying to print a name ten times but I reckon I’m 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;
}

Nightowl · 03-22-2009, 08:51 PM

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.

vart · 03-23-2009, 12:51 AM

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);

hawaiian robots · 03-23-2009, 12:55 AM

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.

vart · 03-23-2009, 12:58 AM

Quote:

Originally Posted by hawaiian robots

Another tip: refrain from using scanf(), it is particularly unsafe,

you should learn to use it correctly

Quote:

fgets() (which I believe is deprecated now)

it is not

Quote:

or even perhaps getline(&buffer, &length, stdin);

I do not think there is standard function like this

03-22-2009, 04:54 PM	#1
Chalmers86 Registered User Join Date: Jan 2009 Posts: 13	For Loop Disaster Currently trying how to use the For loop but I’m not having much luck. Just trying to print a name ten times but I reckon I’m 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; }
Chalmers86 is offline

03-22-2009, 08:51 PM	#2
Nightowl Resu Deretsiger Join Date: Nov 2008 Location: /dev/null Posts: 185	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. __________________ Do as I say, not as I do . . . Experimentation is the essence of programming. Just remember to make a backup first. "I'm a firm believer that <SomeGod> gave us two ears and one mouth for a reason - we are supposed to listen, twice as much as we talk." - LEAF Questions posted by these guidelines are more likely to be answered. Debian GNU/Linux user, with the awesome window manager, the git version control system, and the cmake buildsystem generator. Last edited by Nightowl; 03-22-2009 at 09:03 PM.
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03-23-2009, 12:51 AM	#3
vart CSharpener Join Date: Oct 2006 Posts: 5,242	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); __________________ If I have eight hours for cutting wood, I spend six sharpening my axe.
vart is offline

03-23-2009, 12:55 AM	#4
hawaiian robots Registered User Join Date: Mar 2009 Posts: 8	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.
hawaiian robots is offline

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