int to hex

[cwarn23]

Hi and I am writing a small program but need to make a function that converts an integer to a hex. Below is an example of a similar function but need the result stored in a std::string variable.

printf("%x%x%x%x%x",h0, h1, h2, h3, h4);

Does anybody know how to create a hex() function which will do the same as the above except instead of printing the data it will store the data? I'm also using c++ and hoping this one will work in VC++.

[mrnutty]

Is this what you need :

#include <iostream>
#include <string>
#include <sstream>

using namespace std;

typedef size_t Type;

string toHex(const Type& number){
	stringstream stream;
	stream << hex << number;
	return stream.str();
}
int main(int argc, char *argv[])
{
	string num  = toHex(15);
	cout << num << endl;
 
    return 0;
}

[thomas_naveen]

Have you tried using sprintf to print the hex formatted numbers onto a string.

[cwarn23]

I just tried your function and it only outputs a bunch of numbers. Below is an example of what I'm doing.

#include<iostream>
#include <sstream>
#include <string>

#define rotateleft(x,n) ((x<<n) | (x>>(32-n)))   
#define rotateright(x,n) ((x>>n) | (x<<(32-n)))   



typedef size_t Type;
std::string hex(const Type& number){
	std::stringstream stream;
	stream << hex << number;
	return stream.str();
}

std::string SHA1(unsigned char * str1)   
{   
	int i;
    unsigned long int h0,h1,h2,h3,h4,a,b,c,d,e,f,k,temp;   
    
    h0 = 0x67452301;   
    h1 = 0xEFCDAB89;   
    h2 = 0x98BADCFE;   
    h3 = 0x10325476;   
    h4 = 0xC3D2E1F0;   
    
    unsigned char * str;   
    str = (unsigned char *)malloc(strlen((const char *)str1)+100);   
    strcpy((char *)str,(const char *)str1);   
    
    int current_length = strlen((const char *)str);   
    int original_length = current_length;   
    str[current_length] = 0x80;   
    str[current_length + 1] = '\0';   
    
    char ic = str[current_length];   
    current_length++;   
    
    int ib = current_length % 64;   
    if(ib<56)   
        ib = 56-ib;   
    else   
        ib = 120 - ib;   
    
    for(i=0;i < ib;i++)   
    {   
        str[current_length]=0x00;   
        current_length++;   
    }   
    str[current_length + 1]='\0';   
    
    for(i=0;i<6;i++)   
    {   
        str[current_length]=0x0;   
        current_length++;   
    }   
    str[current_length] = (original_length * 8) / 0x100 ;   
    current_length++;   
    str[current_length] = (original_length * 8) % 0x100;   
    current_length++;   
    str[current_length+i]='\0';   
    
    int number_of_chunks = current_length/64;   
    unsigned long int word[80];   
    for(i=0;i<number_of_chunks;i++)   
    {   
        for(int j=0;j<16;j++)   
        {   
            word[j] = str[i*64 + j*4 + 0] * 0x1000000 + str[i*64 + j*4 + 1] * 0x10000 + str[i*64 + j*4 + 2] * 0x100 + str[i*64 + j*4 + 3];   
        }   
        for(int j=16;j<80;j++)   
        {   
            word[j] = rotateleft((word[j-3] ^ word[j-8] ^ word[j-14] ^ word[j-16]),1);   
        }   
    
        a = h0;   
        b = h1;   
        c = h2;   
        d = h3;   
        e = h4;   
    
        for(int m=0;m<80;m++)   
        {   
            if(m<=19)   
            {   
                f = (b & c) | ((~b) & d);   
                k = 0x5A827999;   
            }   
            else if(m<=39)   
            {   
                f = b ^ c ^ d;   
                k = 0x6ED9EBA1;   
            }   
            else if(m<=59)   
            {   
                f = (b & c) | (b & d) | (c & d);   
                k = 0x8F1BBCDC;   
            }   
            else   
            {   
                f = b ^ c ^ d;   
                k = 0xCA62C1D6;    
            }   
    
            temp = (rotateleft(a,5) + f + e + k + word[m]) & 0xFFFFFFFF;   
            e = d;   
            d = c;   
            c = rotateleft(b,30);   
            b = a;   
            a = temp;   
    
        }   
        h0 = h0 + a;   
        h1 = h1 + b;   
        h2 = h2 + c;   
        h3 = h3 + d;   
        h4 = h4 + e;   
    
    }   
    
	//printf("Hash: %x %x %x %x %x",h0, h1, h2, h3, h4);
	std::string result;
	result=hex(h0);
	result=result.append(hex(h1));
	result=result.append(hex(h2));
	result=result.append(hex(h3));
	result=result.append(hex(h4));
	return result;
}

void main()   
{   
	coda:
	system("CLS");
	std::cout << SHA1((unsigned char *)"The quick brown fox jumps over the lazy dog") << std::endl;
	system("PAUSE");
	goto coda;
}

[mrnutty]

Is this not giving you an error :
"stream << hex << number;" ?

Make it stream <<std::hex << number; "

>> outputs a bunch of numbers
What what do you mean? In hex, just numbers could represent
some decimal numbers as well.

[cwarn23]

Is this not giving you an error :
"stream << hex << number;" ?

Make it stream <<std::hex << number; "

>> outputs a bunch of numbers
What what do you mean? In hex, just numbers could represent
some decimal numbers as well.

Ow, the std::hex was what I was missing and surprisingly I didn't get any errors about that. Thanks for that - rep points added as your a genius.
Problem *Solved*

[Poincarre]

Hi and I am writing a small program but need to make a function that converts an integer to a hex. Below is an example of a similar function but need the result stored in a std::string variable.

printf("%x%x%x%x%x",h0, h1, h2, h3, h4);

Does anybody know how to create a hex() function which will do the same as the above except instead of printing the data it will store the data? I'm also using c++ and hoping this one will work in VC++.

Just use sprintf intead.
Ex:

char buffer[50];

sprintf(buffer, "%x%x%x%x%x",h0, h1, h2, h3, h4 );