UNDER NO CIRCUMSTANCES ARE YOU ALLOWED TO WRITE A SINGLE LOOP!

Question

Simply call on the program, give it one or more parameters and press enter.

The conversion for that specific number should then be displayed unless no arguments were given. If by chance you do not provide the program with any arguments, then the program should display a user prompt, prompting the user to enter a decimal number.

UNDER NO CIRCUMSTANCES ARE YOU ALLOWED TO WRITE A SINGLE LOOP!

So, how would we approach such task?

Recall the structure of your typical C code:

#include <stdio.h>

/* comment. */

int main(int argc, char *argv[])

{

// comment

printf("Hello world")

return 0;

}

Note that main is a function but it takes some arguments.

int main ( int argc, char *argv[] )

These arguments are information about a string which you can pass whenever you run your program.

First, compile your code:

gcc -o Aassign1 Assignment1.c

Then pass in the arguments whenever you execute it

./Aassign1 arg1 agr2....

What do I want?

I need you to write a program that takes in n arguments but requires at least 3 arguments.

1. The first argument should be the base in which you are providing the numbers in.
2. The second arguments should be the base you want to convert to.
3. The third, fourth, and all the way up to n is a sequence of numbers that need to be converted 

 ./Aassign1 decimal binary 1 2 3 4 5 6 7 8 9 10

Loops

YOU UNDER NO CIRCUMSTANCES ARE ALLOWED TO WRITE A SINGLE LOOP!

Bases to cover:

I want you to be able to be able to convert numbers back and forth from Decimal, Hex, and binary.

The structure of your code:

I would like you to write 9 functions that don't change their input (helper functions can) for converting between bases. this means you will need to use malloc to return a 2d array of the result:

char ** decimalToDecimal (...)

char ** decimalToBinary (...)

char ** decimalToHex (...)

char ** binaryToDecimal (...)

char ** binaryToBinary (...)

char ** binaryToHex (...)

char ** hexToDecimal (...)

char ** hexToBinary (...)

char ** hexToHex (...)

void seekUserInput (...)

void freememory(....)

int main (...)

Answer 1

This is challenging to do WITH loops, let alone without...

You must replace every loop with a recursive function.

for example, if array A contains {1,2,3,4,5,6,7,8,9,10}, then to print it forwards, you have to

do something like this:

using namespace std;

#include <iostream>

Show(int * A, int iIndexPos)

{

if (iIndexPos>0)

{

Show(A,iIndexPos-1);

}

cout << A[iIndexPos] << endl;

}

int main()

{

int a[]={1,2,3,4,5,6,7,8,9,10};

int n=10;

Show(a,n-1);

}

Here's some code that does the base conversions

/**************************/

using namespace std;

#include <iostream>

#include <string.h>

#include <stdio.h>

#include <stdlib.h>

#include <math.h>

void GetDecimalNum(int baseFrom, char * numStr, long * runningTotal, int iIndexPos, int maxIndexPos)

{

cout << " iIndexPos =" <<iIndexPos << " : maxIndexPos = " << maxIndexPos << endl;

if (iIndexPos<maxIndexPos)

{

GetDecimalNum(baseFrom,numStr,runningTotal,iIndexPos+1,maxIndexPos);

}

if (iIndexPos<maxIndexPos)

{

int iDigit;

if (baseFrom==16)

{

if (numStr[iIndexPos]>='A' && numStr[iIndexPos]<='F')

{

iDigit = numStr[iIndexPos]-55;

}

else

{

iDigit=numStr[iIndexPos]-48;

}

}

else

{

iDigit = numStr[iIndexPos]-48;

}

*runningTotal = *runningTotal + iDigit * pow(baseFrom,maxIndexPos-iIndexPos-1);

cout << "iDigit is " << iDigit << " : running total is " << *runningTotal << endl;

}

}

void GetMaxExponent(int baseTo, long longIntNum, int * maxExpo )

{

if ((int)pow(baseTo,*maxExpo) < longIntNum)

{

*maxExpo = *maxExpo+1;

GetMaxExponent(baseTo,longIntNum,maxExpo);

}

}

void _convert(int baseTo, long longIntNum, int maxExpo, int curExpo, char * numStr )

{

int iNumDigit;

if (curExpo>0)

{

int denominator = pow(baseTo,curExpo);

iNumDigit = longIntNum/denominator;

if (baseTo==16)

{

if (iNumDigit>=10 && iNumDigit<=15)

{

numStr[maxExpo-curExpo]= char(iNumDigit+55);

}

else

{

numStr[maxExpo-curExpo]= char(iNumDigit+48);

}

}

else

{

numStr[maxExpo-curExpo]=char(iNumDigit+48);

}

longIntNum%=denominator;

_convert(baseTo,longIntNum,maxExpo,curExpo-1,numStr);

}

else

{

if (baseTo==16)

{

if (longIntNum>=10 && longIntNum<=15)

{

numStr[maxExpo-curExpo]= char(longIntNum+55);

}

else

{

numStr[maxExpo-curExpo]= char(longIntNum+48);

}

}

else

{

numStr[maxExpo-curExpo]=char(longIntNum+48);

}

}

}

char * Convert(char * numStr, int baseTo, int baseFrom)

{

char * numStrReturn;

long longIntNum=0;

int strLen = strlen(numStr);

GetDecimalNum(baseFrom,numStr,&longIntNum,0,strLen);

int maxExpo = 0;

GetMaxExponent(baseTo,longIntNum,&maxExpo);

int n = maxExpo+2;

numStrReturn = (char*)malloc(n);

memset(numStrReturn,0,n);

_convert(baseTo,longIntNum,maxExpo,maxExpo,numStrReturn);

return(numStrReturn);

}

char * DoConversion(char * numStrInput, int baseTo, int baseFrom)

{

char * numStrResult = Convert(numStrInput,baseTo,baseFrom);

return(numStrResult);

}

Go ( int baseFrom, int baseTo, int n, char * argv[],int iIndexPos)

{

cout << "Go : iIndexPos = " <<iIndexPos << endl;

if (iIndexPos>3)

{

Go(baseFrom,baseTo,n,argv,iIndexPos-1);

}

char * numStrResult= DoConversion(argv[iIndexPos],baseTo,baseFrom);

cout << numStrResult;

if (numStrResult!=NULL) { free(numStrResult); }

}

int main(int argc, char * argv[])

{

if (argc>=4)

{

int baseFrom = atoi(argv[1]);

int baseTo = atoi(argv[2]);

printf(" command line args: baseFrom = %d : baseTo = %d \n",baseFrom,baseTo);

Go(baseFrom,baseTo,argc,argv,argc);

}

else

{

//seek input

}

}