Thread: question about base 10 to base N convertor lab program

this is my code, i am not sure how to use tags or even what that is, so i apologize if its in the wrong format. it compiles but when i run, say i take the number 26, if i try to take the base 4 of it, it works, or if i take the base 8 it works, but if i take the base 2 it doesnt work? i cant figure it out:? any advice

Code:

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/*This handles up to B64*/
#define B10MAXVAL 100 

void convertToBase(int, int, char [], int);
char toChar(int);
char ans;
void swapspace(char []);
int main()

{
  for (;;) // why doesnt this loop work ?
{
      
char value[B10MAXVAL];
int input = 0;
int base = 10;
   
   /*using scanf %[*][width][modifiers]type*/
  
   
   printf("Please enter the number you wish to convert:\n");
   scanf("%d", &input); 
   fflush(stdin);
   printf("Please enter the base you want to convert to:\n");
   scanf("%d", &base);
   fflush(stdin);
   convertToBase(base, input, value, 0);
   printf("%d converted to base-%d is %s", input, base, value);
   // getchar();
   printf("\n\nDo you wish to run my aswesome program again Y/N?");
   ans = getchar();
   ans = getchar ();
   if (ans=='N' || ans=='n')
      break;
   
}
   printf("\n");
   system("PAUSE");


   return 0;
}

void convertToBase(int base, int number, char outputstring[], int i) {

/*do this by repeatedly dividing and taking the modulus (remainder). */
  int r = 0;
  int result = 0;   
  if (number == 0) { 
	 /*Making sure there is no 0*/       
	 outputstring[i] = 0x30;           
	 outputstring[i+1] = 0;}          
	 
	 /*Divide using mod operator until 0 is reached*/
	 
  r = number % base;
     if(((number-r) == 0)&& ((number - r)!= number)) {
	    outputstring[i] = toChar(r);
	    outputstring[i + 1] = 0;}
  
           else if (((number - r) == number)){
	          outputstring[i] = toChar(number-1);
	          outputstring[i + 1] = 0; }
  
                 else {
                 outputstring[i] = toChar(r);
                 convertToBase(base, ( (number-r)/base ), outputstring, (i+1)); 
     
      /*call swapspace, recursion owns, one of many options, reverse iteration
      or copy_backwards algo in C++ library*/
 }                                         
     if (i == 0) {
	    swapspace(outputstring);}
}

    char toChar(int i){
	char alphabet[] = {'0','1','2','3','4','5','6','7','8','9',
'A','B','C','D','E','F','G','H','I','J','K','L','M',
'N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
'a','b','c','d','e','f','g','h','i','j','k','l','m',
'n','o','p','q','r','s','t','u','v','w','x','y','z','+','/','='};
    return alphabet[i];
}

void swapspace(char string[]){
/*Because we're adding in the wrong direction, we need to swap the order of our value*/
	int i = 0;
	int x = 0;
	char *original;
	
/*here we allocate memory and determine the size of the space needed with 
then we move the string into original, then we free the stack*/
 
	original = (char*)malloc(sizeof(char) * (strlen(string) + 1));//Leave room for null 0
	strcpy(original, string); 
	x = strlen(string); 
	
    while (i < x){
	    string[i] = original[(x-1) - i]; //-1 to kill null zero
	    i++;
	}
	
	string[i] = 0;
    free(original);  

}

> #include <iostream>
If you remove this line, you have a C program.

> fflush(stdin);
SourceForge.net: Fflush - cpwiki

> original = (char*)malloc(sizeof(char) * (strlen(string) + 1));
If you really compile this as C, then you don't need the cast.

> but if i take the base 2 it doesnt work? i cant figure it out:?
So what numbers did you try?
0 in base 2
1 in base 2
2 in base 2
What output did you see?

I notice your function has if / else if / else (3 branches), yet binary can only ever be if / else




If you really want this to be C++, then drop all the printf/scanf/str... functions and find out all the good stuff that is in
#include <iostream>
#include <string>

> this is a old c program that i am trying to convert to c++ for this lab
How about trying to write it yourself?

I've no particular interest in helping people pass a course based on their ability to google and getting others to fix up the code they find to fit their requirements.

Unless you actually understand how to analyse and solve problems yourself, you would be utterly useless in the workplace. Your degree might get you a job, but it would do nothing to help you keep it.

actually dude, i did write that c code myself thank you very much and i am not a computer sci major, but thank you for your condensending attitude after i asked a simple question, all i wanted was a little bit further explaination, congrats! though thanks for the tip about binary and if else, as that was the problem