convert a pointer integer (int**) to String in c

Question

I use the following function to generate a dynamic 2d array in c:

int** Make2DintArray(int arraySizeX, int arraySizeY) { // From http://pleasemakeanote.blogspot.com/2008/06/2d-arrays-in-c-using-malloc.html
    int** theArray;
    theArray = (int**) malloc(arraySizeX*sizeof(int*));
    for (int i = 0; i < arraySizeX; i++)
        theArray[i] = (int*) malloc(arraySizeY*sizeof(int));
    return theArray;
}

I wanted to concatenate all the values of the Matrix (2d - array) to form a string separated by #

I used

int hi11cipherSize = 20;
std::ostringstream text2Encrypt;///ERROR SOURCE
// i used the above function to creat a 2D array and fill it 
// then i used the code below to loop through the record and create the string with delimiter #

for(int i =0; i<hi11cipherSize;i++){
    for(int j =0; j<hi11cipherSize;j++){
        printf("%d \t",HillCipherMatrix[i][j]);
        temp = HillCipherMatrix[i][j];
        text2Encrypt<<(char)temp<<"#";  //// First error cannot concatenate int with char ???

    }   printf("\n");
}

QString tempHLBP = QString::fromStdString(text2Encrypt.str()) ;

qDebug()<<"Text to encrypt "<<tempHLBP<<"\n";
qDebug()<<"Length of string "<<tempHLBP.length();

I get the following ERRORS ERROR :

22:37:59: Running build steps for project StringManJVN...
22:37:59: Configuration unchanged, skipping qmake step.
22:37:59: Starting: "C:\QtSDK\QtCreator\bin\jom.exe" 
main.cpp
main.cpp(17) : error C2079: 'text2Encrypt' uses undefined class 'std::basic_ostringstream<_Elem,_Traits,_Alloc>'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>,
            _Alloc=std::allocator<char>
        ]
main.cpp(27) : error C2297: '<<' : illegal, right operand has type 'const char [2]'
main.cpp(27) : warning C4552: '<<' : operator has no effect; expected operator with side-effect
main.cpp(32) : error C2228: left of '.str' must have class/struct/union
        type is 'int'
jom: C:\QTProject\StringManJVN\Makefile.Debug [debug\main.obj] Error 2
    cl -c -nologo -Zm200 -Zc:wchar_t- -Zi -MDd -GR -EHsc -W3 -w34100 -w34189 -DUNICODE -DWIN32 -DQT_LARGEFILE_SUPPORT -DQT_DLL -DQT_SQL_LIB -DQT_CORE_LIB -DQT_HAVE_MMX -DQT_HAVE_3DNOW -DQT_HAVE_SSE -DQT_HAVE_MMXEXT -DQT_HAVE_SSE2 -DQT_THREAD_SUPPORT -I"..\..\QtSDK\Desktop\Qt\4.8.1\msvc2010\include\QtCore" -I"..\..\QtSDK\Desktop\Qt\4.8.1\msvc2010\include\QtSql" -I"..\..\QtSDK\Desktop\Qt\4.8.1\msvc2010\include" -I"..\..\QtSDK\Desktop\Qt\4.8.1\msvc2010\include\ActiveQt" -I"debug" -I"..\..\QtSDK\Desktop\Qt\4.8.1\msvc2010\mkspecs\win32-msvc2010" -Fodebug\ @C:\Users\SONUT\AppData\Local\Temp\main.obj.3948.0.jom
    C:\QtSDK\QtCreator\bin\jom.exe -f Makefile.Debug

jom 1.0.8 - empower your cores

jom: C:\QTProject\StringManJVN\Makefile [debug] Error 2
22:38:02: The process "C:\QtSDK\QtCreator\bin\jom.exe" exited with code 2.
Error while building project StringManJVN (target: Desktop)
When executing build step 'Make'

Thanks in advance ;-))

@Floris I doubt that is a correct analysis as text2encrypt is an ostream, which should allow any type usage for which the stream operators are defined. I could be wrong though — im so confused
– im so confused, Commented Jun 3, 2013 at 19:10
It doesn't know what text2Encrypt is based on. As mentioned by @AK4749, you may be missing an include — Mike
– Mike, Commented Jun 3, 2013 at 19:20
Even if you resolve your stream inclusion errors, it should be noted that your function returns a local pointer, which is always a bad idea. — ApproachingDarknessFish
– ApproachingDarknessFish, Commented Jun 3, 2013 at 19:54
@valekhalfheart: since the pointer is malloc'ed inside the routine, and that block remains valid, returning the value of the pointer should not be a problem. — Floris
– Floris, Commented Jun 4, 2013 at 0:57

Mike · Accepted Answer · 2013-06-04 11:54:58Z

1

Try to put this at the top:

#include <sstream>

Reading your above question you say that you are trying to put this into a string. If you mean an std::string, doing this is easy. Be sure to include the right string library

#include <string>

and then you can do something like:

int x = 4;
string s = "";
s += x + 48; //this will convert the number 4 into the char value for 4.
             //it works for all ascii numbers
s += "#";    //puts the # sign in there

That more or less will get you what you want. I am not sure if it is the best way, but it sure is easy. Obviously, the steps above are spead out for clarity. You can certainly condense that a bit.

edited Jun 4, 2013 at 11:54

answered Jun 3, 2013 at 19:22

Mike

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3 Comments

Shanil Jevin Over a year ago

Does anyone know a way to concatenate integer with a delimiter "#" Another function than std::ostringstream <<

Shanil Jevin Over a year ago

thanks this solved the problem by simply including #include <sstream> the problem was solved

Mike Over a year ago

Cool, feel free to check it as the answer if it worked for you.

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