Converting from int to CString

Question

TestString::TestString(int num)

This is a conversion constructor that should convert an integer to a string.

For example, if 123 is passed in, the TestString object should store the string data that would be represented by the c-string "123".

class TestString //header file
{
   public:
   TestString (int num);
   //etc.

   private:
   int size;
   char* str;
};

TestString::TestString (int num) //.cpp file 
{
    char c = static_cast<char>(num);

    str = new char[size]; //missing size variable

    int i = 0;

    for (i; cstr[i] != '\0'; i++) //missing cstr array
        str[i] = cstr[i];

    str[i] = cstr[i]; //to tack on null character
}

As you can tell I am missing both the size variable and cstr string in the definition. I don't know if I'm going about this all wrong or just having trouble understanding what sort of setup I'm being asked for...

Any pointers or suggestions greatly appreciated.

Only libraries permitted:

#include <iostream>
#include <iomanip>
#include <cstring>
#include <cctype>

Is there a reason why you want to stay with the `c` functions instead of using the c++ `std::string`. Or is it about `CString` of MS? — t.niese, Mar 20 '15 at 05:18
Personally I prefer string, but cstring was one of the requirements. — JMoore, Mar 20 '15 at 07:25

score 0 · Accepted Answer · answered Mar 20 '15 at 05:22

So by what I understand you want to get the length required for the output string. I guess the only way to do that without <cmath> is using a while loop as such:

int len=0;
int num2=num;
do{
    num2=num2/10;
    len++;
} while (num2>0);

which basically keeps dividing the number by 10 to get how many digits it has.

Then, for each character you can do this: Say you want the character for 0, just use '0'. If you want the character for '1', use '0'+1 which will return 1.

If you need any more help (a full implementation), just comment below and I'll get to you. Have fun!

That's not enough clue. You need `buf[len] = '0' + num2 % 10;` before 'num2 /= 10'. The result string will be backward, it has to be flipped. — Barmak Shemirani, Mar 20 '15 at 06:20

score 0 · Answer 2 · answered Mar 21 '15 at 11:07

0

you don't need any other things than pure vanilla C++ , just use std::to_string:

std::string ouputString = std::to_string(inputInteger);

now you can pull out C-string with std::string::c_str:

ouputString.c_str()

answered Mar 21 '15 at 11:07

David Haim

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Converting from int to CString

2 Answers2