#include <stdio.h>

int main(void)
{
   int i, value;
   const char text[] = "456";
   for (i = 0, value = 0; text [ i ] != '\0'; ++i)
   {
      value *= 10;
      printf("value *= 10 = %3d, ", value);
      value += text [ i ] - '0'; /* add value of current digit character */
      printf("value += '%c' - '0' = %3d\n", text [ i ], value);
   }
   return 0;
}

/* my output
value *= 10 =   0, value += '4' - '0' =   4
value *= 10 =  40, value += '5' - '0' =  45
value *= 10 = 450, value += '6' - '0' = 456
*/

#include <stdio.h>

int main(void)
{
   int i, value;
   const char text[] = "456";
   for ( i = 0, value = 0; text [ i ] != '\0'; ++i )
   {
      int digit = text [ i ] - '0'; /* get value of current digit character */
      printf("value = %3d, %3d * 10 = %3d, ", value, value, value * 10);
      value = 10 * value + digit;
      printf("digit = %d, value = %d\n", digit, value);
   }
   return 0;
}

/* my output
value =   0,   0 * 10 =   0, digit = 4, value = 4
value =   4,   4 * 10 =  40, digit = 5, value = 45
value =  45,  45 * 10 = 450, digit = 6, value = 456
*/

#include <stdlib.h>
#include <iostream.h>
 
main()
{    int val;
      char st[10]
 
        val = 5 + 10;
        itoa(val,st,10) //base 10
        cout <<"decimal: "<<st<<endl;
        itoa(val,st,16)  //hexidecimal
        cout <<"hexidecimal: "<< st << endl;
}