./a.out terminated . Garbage output due to smashing of stack . How to remove this error?

#include <iostream>
#include <fstream>
#include <cstring>
using namespace std;

typedef unsigned long int WORD; /* Should be 32-bit = 4 bytes          */
#define w开发者_如何学编程         32             /* word size in bits                 */
#define r         12             /* number of rounds                  */
#define b         16             /* number of bytes in key            */
#define c          4             /* number words in key               */
                                 /* c = max(1,ceil(8*b/w))            */
#define t         26             /* size of table S = 2*(r+1) words   */
WORD S [t],L[c];                        /* expanded key table                */
WORD P = 0xb7e15163, Q = 0x9e3779b9;    /* magic constants             */
/* Rotation operators. x must be unsigned, to get logical right shift*/
#define ROTL(x,y) (((x)<<(y&(w-1))) | ((x)>>(w-(y&(w-1)))))
#define ROTR(x,y) (((x)>>(y&(w-1))) | ((x)<<(w-(y&(w-1)))))
void RC5_ENCRYPT(WORD *pt, WORD *ct) /* 2 WORD input pt/output ct     */
{ WORD i, A=pt[0]+S[0], B=pt[1]+S[1];
  for (i=1; i<=r; i++)
    { A = ROTL(A^B,B)+S[2*i];
       B = ROTL(B^A,A)+S[2*i+1];
    }
  ct [0] = A ;
  ct [1] = B ;
}
void RC5_DECRYPT(WORD *ct, WORD *pt) /* 2 WORD input ct/output pt     */
{ WORD i, B=ct[1], A=ct[ 0];
  for (i=r; i>0; i--)
    { B = ROTR(B-S [2*i+1],A)^A;
       A = ROTR(A-S [2*i],B)^B;
    }
  pt [1] = B-S [1] ;pt [0] = A-S [0];
}
void RC5_SETUP(unsigned char *K) /* secret input key K 0...b-1]       */
{ WORD i, j, k, u=w/8, A, B, L [c];
   /* Initialize L, then S, then mix key into S */
   for (i=b-1,L[c-1]=0; i!=-1; i--) L[i/u] = (L[i/u]<<8)+K[ i];
   for (S [0]=P,i=1; i<t; i++) S [i] = S [i-1]+Q;
   for (A=B=i=j=k=0; k<3*t; k++,i=(i+1)%t,j=(j+1)%c)      /* 3*t > 3*c */
      { A = S[i] = ROTL(S [i]+(A+B),3);
        B = L[j] = ROTL(L[j]+(A+B),(A+B));
      }
}
void printword(WORD A)
{ WORD k;
  for (k=0 ;k<w; k+=8) printf("%c");
}
int main()
{  
   WORD i, j, k,ptext, pt1 [2], pt2 [2], ct [2] = {0,0};
   ifstream in("key1.txt");
   ifstream in1("plt.txt");
   ofstream out1("cpt.txt");

   if(!in)
   { 
        cout << "Cannot open file.\n"; 
        return 1; 
   }

if(!in1)
   {
        cout << "Cannot open file.\n";
        return 1;
   }



unsigned char key[b];
  in >> key;
  in1 >> pt1[0];
  in1 >> pt1[0];
  if (sizeof(WORD)!=4)
    printf("RC5 error: WORD has %d bytes.\n",sizeof(WORD));







      RC5_SETUP(key);
      RC5_ENCRYPT(pt1,ct);


      printf("\n   plaintext "); printword(pt1 [0]); printword(pt1 [1]);
      printf(" ---> ciphertext "); printword(ct [0]); printword(ct [1]);
      printf("\n");
 RC5_SETUP(key);
 RC5_DECRYPT(ct,pt2);

 out1<<ct[0];
 out1<<ct[1];
 out1 <<"\n";
 printf("\n   plaintext "); printword(pt1 [0]); printword(pt1 [1]);

 return 0;
}

Let the plt.txt file contain 101 100 let the key be 111

go step by step, use getch() to stop your program, make sure you understand the all lines of code and try ddd.

I did not get this error on VS 2008, Win32.

Use a debugger, that should quickly reveal the problem.