Little Program

Posts 1–15 of 21 · Page 1 of 2

Little Program

Hello mpgh'ers,

I have a problem with my C++ program.

This was the assignment:

Write a program that reads keyboard input to the @ symbol and that echoes the input except for digits, converting each uppercase character to lowercase, and vice versa.

And I wrote this:

[HIGHLIGHT=Java]#include <iostream>
#include <cctype>

using namespace std;

int main()
{
char ch;
char line[100];

int i = 0;

cin.get(ch);
while(ch != '@')
{
if(isdigit(ch))
i -= 1;
else if(islower(ch))
{
toupper(ch);
line[i] = ch;
}
else if(isupper(ch))
{
tolower(ch);
line[i] = ch;
}
else
line[i] = ch;
i++;
cin.get(ch);
}

line[i] = '\0';
cout << line;

cout << endl;
system("pause");

return 0;
}[/HIGHLIGHT]

But it shows this:

Anyone know what wrong?

Edit: Changed the code to what I have now. And everything works except the toupper() and tolower().

Ask yourself what this really means in your code you have now.

Code:

line[i] = ch;

Originally Posted by SERG

Ask yourself what this really means

Code:

line[i] = ch;

It means that the letter that is selected in the line array, gets assinged the same letter as in ch.
And that should work.

try this. and i am aware that if an IF statement has one line you dont need to but its good practice. Also it could be that since you didnt specify a delim its using the /n or newline as a delim by default. And since you dont clear the stream its also displaying the garabe kept after your cin.get() (If i remember correctly. P.S Im on codiene pills

)

Code:

  else
            {
                        line[i] = ch;
             }
        i++;
        cin.get(ch);

Originally Posted by wtfiwantthatname

)

Code:

  else
            {
                        line[i] = ch;
             }
        i++;
        cin.get(ch);

So what should my entire code be?

ill give you this much(If you wanna keep it just as a while.) Ill help. Im just not going to do your work for you.

EDIT: Your also using a c-string with out terminating it.

Code:

#include <iostream>
#include <cctype>

using namespace std;

int main()
{
    char ch;
    char line[100];

    int i = 0;
    cin.get(ch);
   while(ch != '@')
   {
        if(isdigit(ch))
            ;
        else if(islower(ch))
        {
            toupper(ch);
            line[i] = ch;
        }
        else if(isupper(ch))
        {
            tolower(ch);
            line[i] = ch;
        }
        else
        {
            line[i] = ch;
        }
        i++;
        cin.get(ch);
       }
    cout << line;
    return 0;
}

Originally Posted by wtfiwantthatname

ill give you this much(If you wanna keep it just as a while.) Ill help. Im just not going to do your work for you.

EDIT: Your also using a c-string with out terminating it.

Code:

#include <iostream>
#include <cctype>

using namespace std;

int main()
{
    char ch;
    char line[100];

    int i = 0;
    cin.get(ch);
   while(ch != '@')
   {
        if(isdigit(ch))
            ;
        else if(islower(ch))
        {
            toupper(ch);
            line[i] = ch;
        }
        else if(isupper(ch))
        {
            tolower(ch);
            line[i] = ch;
        }
        else
        {
            line[i] = ch;
        }
        i++;
        cin.get(ch);
       }
    cout << line;
    return 0;
}

All you did is add "{" and "}"? That doesn't change a lot right?

Originally Posted by Stupid Boy

All you did is add "{" and "}"? That doesn't change a lot right?

Your line buffer isn't null terminated, so cout reads past the actual end of the string inside.

Code:

line[i] = '\0'; // null terminates line

before the cout should work.

Originally Posted by mmbob

Your line buffer isn't null terminated, so cout reads past the actual end of the string inside.

Code:

line[i] = '\0'; // null terminates line

before the cout should work.

Oh yeah, thanks.
I forgot about that.

That fixes the not showing the weird symbols, but why aren't the letters uppercasing and lowercasing?
Edit: I btw know it's something with the toupper() and tolower(). They are all that don't work. So am I using them wrongly or something?

Originally Posted by Stupid Boy

Look at what toupper() and tolower() return. Where are the return values going?

Originally Posted by Stupid Boy

All you did is add "{" and "}"? That doesn't change a lot right?

I said id help not that i would do it for you. I changed that because its just good practice to always use { and } even if your if statement is one line.

Originally Posted by mmbob

Look at what toupper() and tolower() return. Where are the return values going?

I'm sorry but I don't understand that.
toupper() and tolower() are part of the cctype header, so I don't have the function.

Originally Posted by wtfiwantthatname

I said id help not that i would do it for you. I changed that because its just good practice to always use { and } even if your if statement is one line.

Owh okay, thanks then.

Originally Posted by wtfiwantthatname

I said id help not that i would do it for you. I changed that because its just good practice to always use { and } even if your if statement is one line.

You didn't help with his problem at all.

Originally Posted by Stupid Boy

I'm sorry but I don't understand that.
toupper() and tolower() are part of the cctype header, so I don't have the function.

They don't change their parameter. They return the new character. Set ch equal to what toupper() and tolower() return.

Originally Posted by mmbob

They don't change their parameter. They return the new character. Set ch equal to what toupper() and tolower() return.

Ah thanks I got it.
It was supposed to be:

Code:

ch = toupper(ch)

and

Code:

ch = tolower(ch)

You sir need to understand what MSDN is, And that a book is better then a retarded teaches that tastes you only CopyPasta.

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