My program (for a lab)

[Mirai]

It doesn't work. At all. Complains about errors that shouldn't exist.

Anyway, here it is. If you could tell me what I've done hilariously wrong it would help.

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

main()
{

/* Variable Declararion */

struct info {

int age;
int heighti;
int heightft;
char fname[20];
char lname[20];

} retrieve[2];


int wrap, ctr;
int rnum;

/* Loop Input Stage */

printf("Enter the number of inputs you wish to make (0 to quit)");
gets(wrap);

/* Main Information Retrieval Stage */

for (ctr=0; ctr<=wrap; ctr++) {


printf("Enter First Name\n");
gets(retrieve[wrap].fname);
printf("Enter Last Name\n");
gets(retrieve[wrap].lname);
printf("Enter Age\n");
gets(retrieve[wrap].age);
printf("Enter Height in Feet\n");
gets(retrieve[wrap].heightft);
printf("..And Inches?\n");
gets(retrieve[wrap].heighti);

printf("\n\nYour RETRIEVAL NUMBER IS:");
puts(wrap);
}

/* Output Stage */

printf("Enter your RETRIEVAL NUMBER:");
gets(rnum);


printf("Last Name\tFirst Name\tAge\tHeight\n\n");

printf("%s\t%s\t%d\t%dft %din", retrieve[rnum].fname,
retrieve[rnum].lname, retrieve[rnum].age, retrieve[rnum].heightft,
retrieve[rnum].heighti);


return 0;

}

[Cyp]

gets(wrap); &rArr; scanf("%d", &wrap);
gets(retrieve[wrap].age); &rArr; scanf("%d", &retrieve[wrap].age);
gets(retrieve[wrap].heightft); &rArr; scanf("%d", &retrieve[wrap].heightft);
gets(retrieve[wrap].heightin); &rArr; scanf("%d", &retrieve[wrap].heightin);
gets(retrieve[wrap].weightkg); &rArr; scanf("%d", &retrieve[wrap].weightkg);
gets(retrieve[wrap].IQ); &rArr; scanf("%d", &retrieve[wrap].IQ);
puts(wrap); &rArr; printf("%d", wrap);
gets(rnum); &rArr; scanf("%d", &rnum);

Or something like that.

Integers are not strings.


Just looked to see what it's actually supposed to do...

Is it supposed to crash the computer if the user enters any number other than 0 or 1?

If not, you might want to replace wrap with ctr, inside the loop, and add some check that the user didn't type 123456789 or -2147483648.

Also, do you want the user to input one more element than he/she wants to?

for (ctr=0; ctr<=wrap; ctr++) { &rArr; for (ctr=0; ctr<wrap; ctr++) {

[Mirai]

Do I need ctype and string.h in there? The base of this lab was another program I wrote a year ago that used those functions, but after looking at the code, I thought I would ask.

It doesn't hurt to have it in there, even if it does nothing, right?

[Cyp]

Originally posted by Mirai
Do I need ctype and string.h in there? The base of this lab was another program I wrote a year ago that used those functions, but after looking at the code, I thought I would ask.

It doesn't hurt to have it in there, even if it does nothing, right?

Extra header files shouldn't ever hurt. (Unless they were specifically designed to hurt. Doubt the compiler-makers have that kind of tendencies though.)

Note: Was editing the above as I found new things, don't know if you saw all of it.

[Mirai]

Originally posted by Cyp
Extra header files shouldn't ever hurt. (Unless they were specifically designed to hurt. Doubt the compiler-makers have that kind of tendencies though.)

Note: Was editing the above as I found new things, don't know if you saw all of it.

I saw it, and I thank you. On the good side, it compiles without any trouble. On the bad side, it gives some seriously whacked results.

Last Name First Name Age Height

ïwDïw -276903676 -277045620ft -277045620

Any idea what;s going on here?

I'm using GCC to compile the program, if that's of any help.

[Cyp]

Originally posted by Mirai
I saw it, and I thank you. On the good side, it compiles without any trouble. On the bad side, it gives some seriously whacked results.

Last Name First Name Age Height

ïwDïw -276903676 -277045620ft -277045620

Any idea what;s going on here?

I'm using GCC to compile the program, if that's of any help.

In dos, if one input doesn't have the right type (user types "ten" instead of "10"), then all future inputs go completely insane (no idea why, writing my own input routines helps). Don't know if that's relevant without seeing the current version of code.

Don't know about Linux/GCC.

[Nodrog]

scanf sucks, use fgets then sscanf to read in an int.

char input[100]; int age;
printf("Enter your age:\t");
fgets(input, sizeof(input), stdin);
sscanf(input, "%d", &age);

should work.

[Mirai]

the first scanf statement doesn't seem to work (that's the first name scanf).. The program compiles fine, but no matter how many times I run it, the prog always skips the first statement and goes straight on to the second. It's as if it doesn't exist or something. It will still print out the question, but won't stop the program for input.

Anyone know what's up?

[Nodrog]

Originally posted by Mirai
the first scanf statement doesn't seem to work (that's the first name scanf).. The program compiles fine, but no matter how many times I run it, the prog always skips the first statement and goes straight on to the second. It's as if it doesn't exist or something. It will still print out the question, but won't stop the program for input.

Anyone know what's up?

As I said, scanf sucks and you shouldnt use it. Use what I posted above.

If youre determined to use scanf, try scanf("\n%d", &x); instead and see if that fixes it.

[Mirai]

Okay, well, I removed the retrieval number part of the program (it wasn't necessary and was annoying anyway) and just went directly for a listing scheme.

Problems arose..

It seems to be complaining about how a variable doesn't exist - retrieve. However, it is declared as an alias for the structure info.

I need it to be an array or else I have to reprogram pretty much the entire thing. My book is of little help in this scenario..

[Nodrog]

The following code works, if you need anything explained just ask.

#include <stdio.h>

struct info {
	int age;
	int heighti;
	int heightft;
	char fname[20];
	char lname[20];
};

typedef struct info INFO;


int main() {
	INFO *people;
	int i, total;
	char input[100];

	printf("Enter number of inputs (0 to quit): ");
	fgets(input, sizeof(input), stdin);
	sscanf(input, "%d", &total);
 	if (!total) {return 0;}

	people = (INFO *) malloc(sizeof(INFO)*total);

	for (i = 0 ; i != total ; i++) {
		printf("Enter First Name: ");
		fgets((people+i)->fname, sizeof((people+i)->fname), stdin);
		printf("Enter Last Name: ");
		fgets((people+i)->lname, sizeof((people+i)->lname), stdin);
		printf("Enter Age: ");
		fgets(input, sizeof(input), stdin);
		sscanf(input, "%d", &((people+i)->age));
		printf("Enter Height In Feet: ");
		fgets(input, sizeof(input), stdin);
		sscanf(input, "%d", &((people+i)->heightft));
		printf("Enter Height In Inches: ");
		fgets(input, sizeof(input), stdin);
		sscanf(input, "%d", &((people+i)->heighti));
		printf("\n\nYour RETRIEVAL NUMBER IS: %d\n\n", i);
	}

	printf("Enter your RETRIEVAL NUMBER: ");
	fgets(input, sizeof(input), stdin);
	sscanf(input, "%d", &i);
	printf("\n\nLast Name\tFirst Name\tAge\tHeight\n\n");
	printf("%s\t%s\t%d\t%dft %din", (people+i)->fname, (people+i)->lname, (people+i)->age, (people+i)->heightft, (people+i)->heighti);
	return 0;
}

[Mirai]

Well, as happy as I'd like to be to use your code, I can't.

You programmed that in c++. My class is on C. This may clear up some misconceptions.

[meglamaniac]

scanf functions have allways worked fine for me, and they're good for getting formatted input (eg. integers).
eg.

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

main()
{
   int i;

   printf("Input an integer: ");
   if (fscanf(stdin, "%d", &i))
      printf("The integer read was: %i\n", i);
   else
      fprintf(stderr, "Error reading an integer from stdin.\n");
   }
}

The above compiles and runs in my copy of Borland C++ (yes i know, but this is C code as far as I can remember).

And Cyp, wierd things happen in linux with input too.
If you use cin and give it the wrong type of input (a string when it's expecting to go to an int for example) I find it tends to go nuts. The last time I 'tried' it, the result was the program got stuck in an infinate loop of input (god knows where it was getting it from) and eventually quit with a segmentation fault when it ran out of memory.

[Mirai]

Well, it's 5:30 am and I'm really really tired right now. 5 hours of lab will do that to you. Unfortunately, said lab is still uncompleted, and due in approximately 19 hours.

Thank you all, you've been of great help. I'm going to sleep.

[Nodrog]

Originally posted by Mirai
Well, as happy as I'd like to be to use your code, I can't.

You programmed that in c++. My class is on C. This may clear up some misconceptions.

that was pure C...

[Cyp]

I suppose, when correcting
&nbsp; gets(retrieve[wrap].age); &rArr; scanf("%d", &retrieve[wrap].age);
, you didn't also incorrectly correct
&nbsp; gets(retrieve[wrap].fname); &rArr; scanf("%d", &retrieve[wrap].fname);
(Just checking.)

Repasting the latest version of your code should help figure out what's wrong.

[Mirai]

As you can see, I removed some code (like the retrieval number system) that wasn't necessary for the completion of the lab. Instead, it just lists both (or all) names in a spreadsheet type fashion. Although I see problems with that now, I also see a simple for loop can fix them. But the lab states all I need is inputs for at least 2 people.

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

main() 
{

/* Variable Declararion */

struct info {

  int	  age;
  int	  heighti;
  int	  heightft;
  char	  fname[20];
  char	  lname[20];
                 } retrieve[1000];

int wrap, ctr;

/* Main Information Retrieval Stage */

for (ctr=0; ctr<1; ctr++) {
                printf("Enter First Name\n");
                gets(retrieve[ctr].fname);
                printf("Enter Last Name\n");
                gets(retrieve[ctr].lname);
                printf("Enter Age\n");
                scanf("\n%d", &retrieve[ctr].age);
                printf("Enter Height in Feet\n");
                scanf("%d", &retrieve[ctr].heightft);
                printf("..And Inches?\n");
                scanf("%d", &retrieve[ctr].heighti);
                }

/* Output Stage */

printf("Last Name\tFirst Name\tAge\tHeight\n\n");
printf("%s\t%s\t%d\t%dft %din\n", retrieve[1].fname, retrieve[1].lname, retrieve[1].age, retrieve[1].heightft, retrieve[1].heighti);
printf("%s\t%s\t%d\t%dft %din\n", retrieve[2].fname, retrieve[2].lname, retrieve[2].age, retrieve[2].heightft, retreive[2].heighti);

return 0;
}

[Cyp]

So you are inputting one element, elements 0 to 0, then printing two elements, elements 1 to 2.

Printing something that wasn't inputted in the first place could print anything - anything from the meaning of life, to the character 'f' 3^(3^(3^3)) times. Fortunately the printf function isn't self-modifying, so there isn't a risk of it creating an unfriendly AI that will wipe out all life in the universe, unless the output is interpretted/compiled/executed by something somehow.


(array[0] is the first element in an array, not array[1], by the way.)

#include <stdio.h>


main()
{

/* Variable Declararion */

struct info {

int age;
int heighti;
int heightft;
char fname[20];
char lname[20];

} retrieve[2];


int wrap, ctr;
int rnum;

/* Loop Input Stage */

printf("Enter the number of inputs you wish to make (0 to quit): ");
scanf("%d", &wrap);

/* Main Information Retrieval Stage */

for (ctr=0; ctr<wrap; ctr++) {


printf("Enter First Name: ");
scanf("%s", retrieve[ctr].fname);
printf("Enter Last Name: ");
scanf("%s", retrieve[ctr].lname);
printf("Enter Age: ");
scanf("%d", &retrieve[ctr].age);
printf("Enter Height in Feet: ");
scanf("%d", &retrieve[ctr].heightft);
printf("..And Inches?: ");
scanf("%d", &retrieve[ctr].heighti);
printf("\nYour RETRIEVAL NUMBER IS: %d\n\n", wrap);

}

/* Output Stage */

printf("Enter your RETRIEVAL NUMBER:");
scanf("%d", &rnum);


printf("Last Name\tFirst Name\tAge\tHeight\n\n");

printf("%s\t%s\t%d\t%dft %din", retrieve[rnum].fname,
retrieve[rnum].lname, retrieve[rnum].age, retrieve[rnum].heightft,
retrieve[rnum].heighti);


return 0;

}

try this ^^