I am using C++ and I need help with a program question dealing with string/function call)?

Let's say I have a function defined as





str_call (int x)





When I do str_call(0), I want the function to return the string


"Ninety"...





How can I write up the function? I have no experience dealing with strings.

I am using C++ and I need help with a program question dealing with string/function call)?
See below for an example of a function that returns a string. The functionality you're looking for calls, I think, for a lookup table. The example also illustrates that.





By the nature of your question, I assume you're something of a beginner in C++. Some of the things you see below may be new to you, but it's never too soon to learn. C++ offers many useful features, and you should learn to take advantage of them.





#include %26lt;iostream%26gt;


#include %26lt;string%26gt;


#include %26lt;map%26gt;





using namespace std;





typedef map%26lt;int,string%26gt; LookupTable;


typedef pair%26lt;int,string%26gt; LookupTableElement;





string translate(int,const LookupTable%26amp;);





int main(int argc, char *argv[]) {


LookupTable lookup;





// Initialize


lookup.insert(LookupTableElement(0,strin...


lookup.insert(LookupTableElement(1,strin...


// ...


lookup.insert(LookupTableElement(90,stri...





// Translate


cout %26lt;%26lt; translate(90,lookup) %26lt;%26lt; endl;


cout %26lt;%26lt; translate(99,lookup) %26lt;%26lt; endl;





return 0;


}





string translate(int x,const LookupTable%26amp; map) {


LookupTable::const_iterator i;


if ((i = map.find(x)) != map.end()) {


return i-%26gt;second;


} else {


return string("not found");


}


}





// Program output:


// ninety


// not found
Reply:I doubt you're dumb, you just haven't learned enough C++ yet. For now, you can skip over the more complicated stuff. The fundamentals of what you asked for - how to return a string from a function - are fairly simple, and clearly shown in my 'translate' function. Report It

Reply:When dealing with strings as output parameters of functions, it's best to provide the function a buffer for filling it up. For example:





bool str_call(int x, char *result, int resultSize)


{


if (x==0)


{


if (resultSize%26gt;=strlen("Ninety")) // check to see if the provided buffer is big enough


{


strcpy(result, "Ninety");


return true; // return a successfull return code


}


}





return false; // result isn't valid


}





void main()


{


char result[100] = { '\0' };





if (str_call(0, result, sizeof(result))==true) // Calling the str_call function


{


printf("%s\n", result);


}


};





// Have fun,


// S. B.
Reply:You have two options. If you only ever want to return the one string, "ninety", then you can do this:





char *str_call(int x)


{


return "ninety";


}





my_other_function()


{


printf ("%s\n", str_call(0)); // Prints "ninety"


}








This is OK, but it's a bit limited. A better option would be to have something like this:








char *str_call(int x, char *storage)


{


strcpy(storage, "ninety");


return storage;


}





my_other_function()


{


char str[20];


printf ("str_call returns %s\n", str_call(0, str)); // Prints "str_call returns ninety"


printf ("Also, str = %s\n", str); // Prints "Also, str = ninety"


}








For completeness it's better to set limits on the size of these arrays, so you'd have this:





char *str_call(int x, char *storage, int maxlen)


{


strncpy(storage, "ninety", maxlen);


return storage;


}





my_other_function()


{


const int strSize = 20;


char str[strSize];


printf ("str_call returns %s\n", str_call(0, str, strSize)); // Prints "str_call returns ninety"


printf ("Also, str = %s\n", str); // Prints "Also, str = ninety"


}








Finally, if you're using C++ then you may as well also use the benefits of STL like this:





void str_call(int x, std::string %26amp;storage)


{


storage = "ninety";


}





my_other_function()


{


std::string str;


str_call(0, str);


printf ("str = %s\n", str); // Prints "str = ninety"


}
Reply:Have a read about pointers.





Strings are arrays of characters. when passing an array, you should pass a pointer the memory address of the first element in the array.





char mystring[50]





char* StringFunction(int x){


char mystring2[50];


strcpy(mystring2, "Ninety");


return mystring2;


}





int main(){


mystring = StringFunction(0);


cout %26lt;%26lt; mystring;


return 0;


}


__





I havnt been learning C++ long, but try compiling that. I can't garuntee it is the most efficient way even if it does work, but it might give you a start
Reply:go to www.freeprogrammersheaven.com and search you can learn and will get the answers