Veteran - Problem 6, Solution in c

/*
	Weird Math
*/

#include <stdio.h>
#include <string.h>

/* I use strings in this solution but it could be solved numerically...
LOG (base 10) could be used to find the length
of the code....  Integer division & Modulus could be used to
grab each digit.

My arrays could be replaced with switch/if statements
*/

main(int argc)
{
int z;
int numOfLoops;
int SHOWSTEPS=argc-1;  /*  SET THIS TO NON-ZERO TO SEE THE STEPS OF THE CALCULATIONS */
int code;
unsigned i;
unsigned numdigits;
int a,b,c;
char op;
char OPERATOR[]={'*','+','-','!'};
char temp[20], Astr[20], Bstr[20];
/*   Prof:  9 7 8 0 4 5 6 1 2 3
     US  :  0 1 2 3 4 5 6 7 8 9
*/

char  CONVERT [255];
CONVERT['7']='0';
CONVERT['8']='1';
CONVERT['9']='2';
CONVERT['0']='3';
CONVERT['4']='4';
CONVERT['5']='5';
CONVERT['6']='6';
CONVERT['1']='7';
CONVERT['2']='8';
CONVERT['3']='9';

code=1;
scanf("%d",&numOfLoops);

for (z=0; z<numOfLoops; z++)
 { // do each number
	scanf("%d",&code);

	if (code==-1)
		return 0;

	temp[0]=0;

	sprintf(temp,"%d",code);  /* I'm lazy at finding digits of integers */

	numdigits=temp[0]-'0';

	if (strlen(temp) < numdigits+2)
	 { // validate test
		printf("ERROR!!!!! INVALID TEST DATA!!!!!!!!!!!!\n");
		return 1;
	 } // validate test

	if (SHOWSTEPS) printf("A has %d digits\n",numdigits);
	if (SHOWSTEPS) printf("------------------------------\n");
	if (SHOWSTEPS) printf("  Before Conversion  : \n");
	if (SHOWSTEPS) printf("------------------------------\n");

	strncpy(Astr,temp+1,numdigits);  Astr[numdigits]=0;
	strncpy(Bstr,temp+2+numdigits,strlen(temp) - numdigits);
	op=OPERATOR [ (temp[1+numdigits]-'0') % 3];

	if (SHOWSTEPS) printf("Astr=[%s]\nBstr=[%s]\nOp: %c\n",Astr,Bstr,op);
	if (SHOWSTEPS) printf("------------------------------\n");
	if (SHOWSTEPS) printf("   After Conversion  : \n");
	if (SHOWSTEPS) printf("------------------------------\n");
	for (i=0; i < strlen(Astr); i++)
		 Astr[i]=CONVERT [ Astr[i] ];

	for (i=0; i < strlen(Bstr); i++)
		 Bstr[i]=CONVERT [ Bstr[i] ];
	if (SHOWSTEPS) printf("Astr=[%s]\nBstr=[%s]\nOp: %c\n",Astr,Bstr,op);

	sscanf(Astr,"%d",&a);
	sscanf(Bstr,"%d",&b);

	if (op=='*') c=a*b;
	if (op=='+') c=a+b;
	if (op=='-') c=a-b;

	printf ("%4d %c %4d = %4d\n",a,op,b,c);
 } // do each number

}