Thread: Validate area codes within a list of area codes

I need help with my code. When I have i set to zero and I enter the first area code listed it says that it is a valid area code. However when I enter the next area code listed it says that it is an invalid area code, but it should actually be valid.

Can someone help me figure out what I need to change so that when I enter each of the four area codes listed it says that they are valid area codes and when I enter any other area code it says that it is invalid. Thank you

Code:

 9 #include <stdio.h>
10 
11 int main ()
12 {
13 
14    
15    int codes [4] = {303, 970, 720, 719};
16    int codeToFind = 0;
17    int codeToCheck = 0;
18    int i = 0;
19    
20    
21    printf("Enter area code to validate: ");
22    scanf("%d", &codeToFind);
23    
24    for(i = 1; i < 4; i++)
25    {
26       
27    if(codeToFind == codes[i])
28    {
29        printf("Valid Area Code");
30    }
31    else
32    {
33       printf("Invalid Area Code");
34    }
35       
36    return 0;
37 }
38 }

Ok, I tried that and now it doesn't print anything after entering an area code. When I set i = 0 it will give me the correct output for the first area code listed which is 303, but for all of the others listed it says they are invalid. I think I have to change something with my for loop, but I haven't quite figured it out yet

I tried that too and it is still not working, now it says every number I put in is a valid area code and the exit code for the process is 15 rather than zero.

Thank you for reminding me of the indentations

Here is my current code and it is pretty messed up. When I compile it tells me that line 29 is not a function. I am not sure if this is the best way to accomplish the task, I am very new to this.

I don't really know how to write my own function very well, which is why I was not doing that with the previous code. I know the previous code can work with a few tweaks, but I haven't been able to figure out how to make it work yet.

Thank you for any assistance

Code:

 9 #include <stdio.h>
10 
11 int validCodes(int codes);
12 
13 int main ()
14 {
15 
16    int codes [4] = {303, 720, 719, 970};
17    int codeToFind = 0;
18    int codeToCheck = 0;
19    int i = 0;
20    int used = 4;
21    int validCode = 0;
22    
23    
24    
25    printf("Enter area code to validate: ");
26     if (scanf("%d", &validCode) == 1)
27       {
28       
29           if (validCode(codes));
30           {
31              printf("Area code is valid"); 
32           }
33           else
34           {
35             printf("Area code is not valid");
36           }
37       }
38     else
39     {
40         printf("please try again");
41     }
42  
43     return 0;
44 }
45 
46       
47         
48 int validCodes(int codes)
49 {
50    int validCodes[] = {303, 970, 720, 719};
51    for(i = 0; i < 4; i++)
52    ans = codes[i]
53    return ans;
54 }

I thought I replied yesterday, but I guess it didn't post.

I do not understand everything about post 4, I am not very good at writing functions or calling them in my program and no matter how I change things around i still get the same error that it is not a function.

I do get that I should not be printing on every iteration of the loop, but I still haven't figured out how to fix this issue. So needless to say my program is still printing every entry as valid when they are not all valid

You should start by posting your latest code, along with any compiler warnings/errors you're receiving.

You should also post code that is compilable ... that is, don't include line numbers (that is done for you automatically by the forum software).

Make sure your code is neatly formatted and indented. As a courtesy, this is what it should look like:

Code:

#include <stdio.h>

int validCodes(int codes);

int main ()
{
    int codes [4] = {303, 720, 719, 970};
    int codeToFind = 0;
    int codeToCheck = 0;
    int i = 0;
    int used = 4;
    int validCode = 0;

    printf("Enter area code to validate: ");

    if (scanf("%d", &validCode) == 1)
    {
        if (validCode(codes));
        {
            printf("Area code is valid");
        }
        else
        {
            printf("Area code is not valid");
        }
    }
    else
    {
        printf("please try again");
    }

    return 0;
}

int validCodes(int codes)
{
    int validCodes[] = {303, 970, 720, 719};

    for(i = 0; i < 4; i++)
        ans = codes[i]

    return ans;
}

The first mistake is a basic one ... on line 18, you end the "if()" with a semi-colon. That is not what you want.

In C, a semi-colon by itself is considered a valid statement (referred to as a "null statement"). It essentially means "do nothing". That is what you get by placing a semi-colon after the "if".

For instance, in the following code, you would expect the print statement not to print:

Code:

int x = 5;

if(x > 10);
    printf("x is %d\n",x);

But it does print. Because of the misplaced semi-colon, the code is really interpreted as this:

Code:

int x = 5;

if(x > 10)
    ;
printf("x is %d\n",x);

Regardless of the value of "x", the print statement is executed. If "x" is not greater than 10, the "if" fails and the rest of the code (including the print) occurs. If "x" is greater than 10, then the "if" is true ... but the null statement says nothing is to occur ... and the rest of the code (i.e. the print) still happens.

Your code has still other errors.

You're using the variables "i" and "ans" in the "validCodes()" function, but you don't declare those variables in that function.

If you pass an array to a function, you need to declare it as an array (or a pointer) in the function parameter list.

And in your "validCodes()" function, you're not using the "validCodes" array for anything.