Thread: Debugging issue

I'm trying to debug a fairly simple function that is suppose to take a string and convert any lowercase letters to uppercase. Unfortanitly I am getting a large number of errors I do not know how to fix (using codeblocks)

the code is as follows:

Code:

/*
This function accepts a string and returns a string with any lowercase letters found in it to uppercase letters
@param inputString:  This is the string to be converted
@return: The upperCase string
*/

string toUpper(string inputString)
{
    for(int i=0; i<inputString.length(); i++)
    {
            if(inputString[i]=="a")
            inputString[i]="A";
            else if(inputString[i]=="b")
            inputString[i]="B";
            else if(inputString[i]=="c")
            inputString[i]="C";
            else if(inputString[i]=="d")
            inputString[i]="D";
            else if(inputString[i]=="e")
            inputString[i]="E";
            else if(inputString[i]=="f")
            inputString[i]="F";
            else if(inputString[i]=="g")
            inputString[i]="G";
            else if(inputString[i]=="h")
            inputString[i]="H";
            else if(inputString[i]=="i")
            inputString[i]="I";
            else if(inputString[i]=="j")
            inputString[i]="J";
            else if(inputString[i]=="k")
            inputString[i]="K";
            else if(inputString[i]=="l")
            inputString[i]="L";
            else if(inputString[i]=="m")
            inputString[i]="M";
            else if(inputString[i]=="n")
            inputString[i]="N";
            else if(inputString[i]=="o")
            inputString[i]="O";
            else if(inputString[i]=="p")
            inputString[i]="P";
            else if(inputString[i]=="q")
            inputString[i]="Q";
            else if(inputString[i]=="r")
            inputString[i]="R";
            else if(inputString[i]=="s")
            inputString[i]="S";
            else if(inputString[i]=="t")
            inputString[i]="T";
            else if(inputString[i]=="u")
            inputString[i]="U";
            else if(inputString[i]=="v")
            inputString[i]="V";
            else if(inputString[i]=="w")
            inputString[i]="W";
            else if(inputString[i]=="x")
            inputString[i]="X";
            else if(inputString[i]=="y")
            inputString[i]="Y";
            else if(inputString[i]=="z")
            inputString[i]="Z";
    }

}

The main errors I am getting are:
/home/hewhosurvives/c++/order/item.h||In member function ‘bool item::load(std::ifstream&)’:|
/home/hewhosurvives/c++/order/item.h|101|warning: comparison between signed and unsigned integer expressions|
/home/hewhosurvives/c++/order/functions.h||In function ‘std::string toUpper(std::string)’:|
/home/hewhosurvives/c++/order/functions.h|21|warning: comparison between signed and unsigned integer expressions|
/home/hewhosurvives/c++/order/functions.h|23|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|23|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|24|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|25|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|25|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|26|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|27|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|27|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|28|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|29|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|29|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|30|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|31|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|31|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|32|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|33|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|33|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|34|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|35|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|35|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|36|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|37|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|37|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|38|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|39|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|39|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|40|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|41|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|41|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|42|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|43|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|43|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|44|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|45|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|45|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|46|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|47|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|47|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|48|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|49|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|49|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|50|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|51|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|51|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|52|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|53|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|53|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|54|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|55|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|55|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|56|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|57|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|57|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|58|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|59|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|59|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|60|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|61|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|61|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|62|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|63|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|63|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|64|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|65|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|65|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|66|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|67|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|67|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|68|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|69|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|69|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|70|error: invalid conversion from ‘const char*’ to ‘char’|
/home/hewhosurvives/c++/order/functions.h|71|warning: comparison with string literal results in unspecified behaviour|
/home/hewhosurvives/c++/order/functions.h|71|error: ISO C++ forbids comparison between pointer and integer|
/home/hewhosurvives/c++/order/functions.h|72|error: invalid conversion from ‘const char*’ to ‘char’|
||More errors follow but not being shown.|
||Edit the max errors limit in compiler options...|
||=== Build finished: 50 errors, 27 warnings ===|

Any ideas how I can fix it or what I am doing wrong?

A string is composed of characters. For example, "hello" is

Code:

{ 'h', 'e', 'l', 'l', 'o', 0 }

so you would use the same syntax if you were assigning a part of it like
s[3] = 'L';

Now, do you know of any easier way to do this than a long if/else if/else tree?

hint: look into the standard library

What a nasty toUpper function. I think the errors are fairly straightforward there.

I can find at least a dozen things wrong in Nor's posts. All the replies above them are fine.

Originally Posted by cyberfish

I can find at least a dozen things wrong in Nor's posts..

I'm game:
1. No capitals!
2. It should be ctype.c, not string.c.
3. It shouldn't even be ctype.c, but cctype.
4. It shouldn't even be cctype, because we are using C++ strings.
5. "right" should be "write"
6. No comma between "own" and "try".
Half way there in the first two lines and I haven't even touched the code!
Whoops, there goes my attention span ...

This is what happens during this moron thing I do called testing ...

Before: pLease ... be kind, debug before POSTING!!
After : pLease@NNN@be@kindL@debug@before@POSTINGAA

Something seem wrong to you?
Take the hint.

there is a special string function in <string.c> i think.

It is in <cctype>, and it doesn't work on strings, but work on chars.

Code:

string toUpper(string inputString)
{
    for(int i=0; i<inputString.length(); i++)
    {
            if( inputString[i] < 'Z' )
            inputString[i]+= ('a' - 'A'); //  'a' - 'A' = i32
                }

}

1. Indentation!
2. the function should return a string
3. "if( inputString[i] < 'Z' )" what if it's not a letter?
4. it will only work if the computer uses ASCII. some don't

Code:

void toUpper(char* inputString)
{
    //size_t and unsigned int(32/64) are one and the same
    size_t length = strlen(inputString);

    for(;length; length--, inputString++)
    {
            if( *inputString <= 'A' )
                *inputString += ('a' - 'A'); //  'a' - 'A' = i32
    }

}

This is known as premature optimization. Worse still, in this case, the code is probably not any faster if not slower, and definitely a lot less readable. It is pointless.

Code:

std::string Myname = "Nor";
toUpper(Myname);
std::cout << Myname;

Yes, you are indeed wrong.

1. the string is passed by value (copied, the original string is not modified)
2. A std::string cannot be converted to a char* like that. That's what the c_str() member function of the std::string class is for. Even that will only give you a "const char *", so you cannot modify it inside the function.

It may sound a little hypocritical, but when I said I can find a dozen things wrong in your post, I wasn't referring to the English, but the code. It's an C++ forum afterall, and not everyone's native language is English (mine isn't either).

Anyways, I would've implemented it like this -

Code:

#include <cctype>
...
void str_to_upper(std::string &str) { //pass by reference
    for (size_t i = 0; i < str.size(); i++) {
        str[i] = (char) toupper(str[i]); //toupper returns the input if the input has no uppercase equiv.
    }
}