An instance of an itoa function implemented in the C language

1. The prototype:

char *itoa( int value, char *string,int radix);

2. Function description:

value: data to be converted. string: the address of the destination string. radix: the converted base number, which can be 10, 16, etc.

3. Simple implementation of the function:

#include <iostream>
#include <string>
using namespace std;

char* My_itoa(int value,char str[],int radix)
{
  char temp[33];
  char *tp = temp;
  int i;
  unsigned v;
  int sign;
  char *sp;
  if(radix > 36 || radix < 1)
    return 0;
  sign = (radix == 10 && value < 0); //10 Hexadecimal negative
  if(sign)
    v = -value;
  else
    v = (unsigned)value;
  while(v || tp == temp)       // Into operation
  {
    i = v % radix;
    v = v / radix;
    if(i < 10)
      *tp++ = i + '0';
    else
      *tp++ = i + 'a' - 10;
  }
  if(str == 0)
    str = (char*)malloc((tp - temp) + sign + 1);
  sp = str;
  if(sign)   // If it's a negative number, I'm going to put the minus sign into the array first
    *sp++ = '-';
  while(tp > temp)
    *sp++ = *--tp;
  *sp = 0;

  return str;
}

int main()
{
  long int num;
  int radix;   // The decimal representation of the input
  char str[256];
  cout<<" Please enter integers and base Numbers: ";
  cin>>num>>radix;
  My_itoa(num,str,radix);
  cout<<" After the integer is converted to a string: ";
  cout<<str<<endl;

  return 0;
}

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