Need help 3:

[high girder]

Im struggling with my program atm
Im trying to get this to work:

char *p = 'A';
char inputs[AR_SIZE];
char userChars[4];
double *userNums[3] = {0,0,0};

while (p != 'Z') {


    gets(inputs);

    p = inputs[0];

    if (!charEval(inputs)) {
        printf("%s", error1);
    }

    //Zero Terminates String
    inputs[strlen(inputs)] = "\0";

    //Checks to see if all fields are fufilled
    if (sscanf(inputs, "%3s %lf %lf %lf", userChars, &userNums, &userNums[1], &userNums[2]) != 4) {
        printf("%s", error1);

    }
    else {
        sscanf(inputs, "%3s %lf %lf %lf", userChars, userNums, &userNums[1], &userNums[2]);
        printf("%lf", userNums);
    }

-This program is intended to force users to follow a format string indicated in sscanf
-My issue is that it is not reading any numbers in on the else statment, it will always make each value zero
-I have no clue what im doing wrong, the eval string is "CCC Num Num Num", it should be working

[idle cedar]

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[elfin sorrel]

!f

[idle cedar]

Im struggling with my program atm
Im trying to get this to work:

char* p = 'A';
char inputs[AR_SIZE];
char userChars[4];
double* userNums[3] = {0, 0, 0};

while (p != 'Z') {
  gets(inputs);

  p = inputs[0];

  if (!charEval(inputs)) {
    printf("%s", error1);
  }

  // Zero Terminates String
  inputs[strlen(inputs)] = "\0";

  // Checks to see if all fields are fufilled
  if (sscanf(inputs, "%3s %lf %lf %lf", userChars, &userNums, &userNums[1],
             &userNums[2]) != 4) {
    printf("%s", error1);

  } else {
    sscanf(inputs, "%3s %lf %lf %lf", userChars, userNums, &userNums[1],
           &userNums[2]);
    printf("%lf", userNums);
  }

-This program is intended to force users to follow a format string indicated in sscanf
-My issue is that it is not reading any numbers in on the else statment, it will always make each value zero
-I have no clue what im doing wrong, the eval string is "CCC Num Num Num", it should be working

Weeb

Formatted by potatoalienof13

[high girder]

the getsline is used instead of scanf because i want to be able to avoid newlines

i have a hunch that because im not using scanf here, thats where the issue is occuring

because gets reads spaces as though they were characters

[elfin sorrel]

okay, first of all, char *p = 'a'; is not correct

[high girder]

ignore the poiner for userNums btw

it isn't?

[elfin sorrel]

you probably meant just char p = 'a'

[high girder]

im just trying to stop the program when z is inputted

oh

pointer variables confuse me

i have no idea why i would have to use them in most scenarios i see them being used

[rapid dune]

indirection will be useful when they are useful

[elfin sorrel]

in the first sscanf, &userNums should really be &userNums[0]

[high girder]

why?

dosent it assume your referring to the first address spot if none is provided

[elfin sorrel]

accessing an array with [] removes one level of indirection

[rapid dune]

double* [] doesn't seem like what you want

[high girder]

yee

[elfin sorrel]

using & adds one

[high girder]

i was just testing stuff

wdym by adds one

like it adds an address spot>

*?

[elfin sorrel]

yeah, char* becomes char**

[high girder]

oh

[elfin sorrel]

sscanf just wants one level of indirection, you are giving it two

[high girder]

wdym by indirection

[elfin sorrel]

level of pointerness

[high girder]

oh

so how many addresses are being pointed too

[elfin sorrel]

with &userNums it creates a pointer pointing to another pointer that points to userNums

[high girder]

and without it it's just one pointer correct?

or zero

[elfin sorrel]

its just one

double* userNums[3] = {0, 0, 0};``` also yeah this should probably be `double userNums[3]`

[high girder]

whats the difference?

ik ones a pointer variable

and one isnt

but whats the primary difference between the two?

i mean dont variables point to addresses regardless

[elfin sorrel]

the first is an array of pointers to doubles, the second is an array of doubles

[elfin sorrel]

variables live at addresses

[high girder]

and pointers point to those addresses-right?

[elfin sorrel]

pointers are just variables that contain another address

yeah

[high girder]

so variables by themselves dont point to where they are located

right?

[elfin sorrel]

yeah

[high girder]

they need a variable that points to where they are located

that makes sense

okay so how would you rewrite this?

should i put &'s on everything

or just the userNums

[elfin sorrel]

just the userNums

[high girder]

so heres what i've got:

scanf(inputs, "%3s %lf %lf %lf", userChars, &userNums[0], &userNums[1], &userNums[2]);
printf("%lf", userNums);

its still not inputting the number into it

idk why

[elfin sorrel]

cant print arrays with printf

you need to iterate over it

[high girder]

not even array index spots?

[elfin sorrel]

you can print array elements, just not entire arrays

[high girder]

okay so i've got it to work now

one last question

[elfin sorrel]

btw, inputs[strlen(inputs)] = '\0' will do nothing

[high girder]

it wont?

i was trying to zero terimnate it

[elfin sorrel]

strlen returns the index of the null terminator

[high girder]

oh

[elfin sorrel]

gets adds one

[high girder]

didnt know that

[elfin sorrel]

btw

dont use gets()

[high girder]

is there another way i can avoid newlines from being entered before all fields are provided?

[elfin sorrel]

its removed from newer standards, and is seriously frowned upon

[high girder]

didnt realize that

[elfin sorrel]

use fgets

[high girder]

fgets?

[elfin sorrel]

yes,

  fgets(inputs, AR_SIZE, stdin);

[high girder]

ooo okay

why is gets frowned upon?

i thought fgets was for files so i havent used it yet

[elfin sorrel]

if someone inputs a line longer than the buffer that you pass to gets, anything can happen

its UB

[high girder]

oh so you have to provide a massive buffer in order to avoid weird stuff from hapening

for example making a string have more index spots then what would normally be inputted

at least thats what im gathering

[elfin sorrel]

input might be different than you expected

no matter how big you make the buffer, it can still overflow with gets

[high girder]

oh danm

okay ill try that then thanks

thats it for now i think

thankyou

!solved