toupper function

hello all I having a bit of trouble with this little bit of code. observe

Code:

---

#include <iostream.h>
int main()
{
        const int NUMCHARS = 80;
        char strng[80];
        int i = 0;
        char ToUpper(char ch);
        cout<<"Enter a line of text\n";
        cin.getline(strng,NUMCHARS);

                while (strng[i] != '\0')
                {
                        strng[i] = ToUpper(strng[i]);
                        i++;
                }

                cout<<"the string with uppercase letters";
                cout<<  strng <<endl;
                return 0;
}

ToUpper(char ch)
{
       
        if (ch >= 'a' && ch <= 'z')
                return (ch - 'a' + 'A');
        else
                return(ch);
}

---

I keep getting error messages saying unresolved external. I've been reading oup on how to convert lower to uppercase letters and if there is an easier way any input would be appreciated thanks and God bless

Since your function returns a Char you need to declare it as a char.

char ToUpper(char ch)

details details details, One can never be to careful about them you know

Code:

---

       
        if (ch >= 'a' && ch <= 'z')
                return (ch - 'a' + 'A');
        else
                return(ch);
}

---

excuse me .. but can you tell me what is this function for?

is it for detection of upper case?

and what do u mean by

Code:

---

return(ch-'a'+'A');

---

thanks in advance

Well the code is designed to change lower case to uppercase. here is the final copy and it is working thanks to all of my dear friends here who helped me find my simple mistake here is the working code

Code:

---

#include <iostream.h>
int main()
{
        const int NUMCHARS = 80;
        char strng[80];
        int i = 0;
        char ToUpper(char ch);
        cout<<"Enter a line of text\n";
        cin.getline(strng,NUMCHARS);

                while (strng[i] != '\0')
                {
                        strng[i] = ToUpper(strng[i]);
                        i++;
                }

                cout<<"the string with uppercase letters\n";
                cout<<  strng <<endl;
                return 0;
}

char ToUpper(char ch)
{
       
        if (ch >= 'a' && ch <= 'z')
                return (ch - 'a' + 'A');
        else
                return(ch);
}

---

thank you kindly manofsteel972 for noticing the oversight

> if there is an easier way
Yeah, use the toupper() in ctype.h

> return (ch - 'a' + 'A');
This only works on character sets which are contiguous through the alphabet - for example ASCII.
The EBCDIC character set for example is not contiguous.