我写了这个代码，看起来它能正常工作：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int Counter (FILE * fp);
void MergePrint (char * lhalf, char * rhalf);
void Down(FILE * fp1, FILE * fp2, char * lhalf, char * rhalf, int n);
int SmallNums (FILE * fp1, int n);
int ReverseNum (int n);
int main(int argc, char* argv[])
{
int dig;
char * lhalf = NULL, * rhalf = NULL;
unsigned int len_max = 128;
unsigned int current_size_k = 128;
unsigned int current_size_l = 128;
lhalf = (char *)malloc(len_max);
rhalf =(char *)malloc(len_max);
FILE * fp1, * fp2;
fp1 = fopen(argv[1],"r");
fp2 = fopen(argv[1],"r");
dig = Counter(fp1);
if ( dig < 3)
{
printf("%i\n",SmallNums(fp1,dig));
}
else
{
int a,b,prison = 0, ten = 0, i = 0,j = dig -1, k = 0, l = 0;
fseek(fp1,i,0);
fseek(fp2,j,0);
if ((a = fgetc(fp1)- '0') == 1)
{
if ((fgetc(fp1)- '0') == 0 && (fgetc(fp2) - '0') == 9)
{
lhalf[k] = '9';
rhalf[l] = '0';
i++; j--;
k++; l++;
}
i++;
prison = 0;
ten = 1;
}
while (i <= j)
{
fseek(fp1,i,0);
fseek(fp2,j,0);
a = fgetc(fp1) - '0';
b = fgetc(fp2) - '0';
if ( j - i == 1)
{
if ( (a == b) && (ten == 1) && (prison == 0) )
Down(fp1,fp2,lhalf,rhalf,0);
}
if (i == j)
{
if (ten == 1)
{
if (prison == 1)
{
int c;
c = a + 9;
if ( c%2 != 0)
Down(fp1,fp2,lhalf,rhalf,0);
lhalf[k] = c/2 + '0';
k++;
}
else
{
int c;
c = a + 10;
if ( c%2 != 0)
Down(fp1,fp2,lhalf,rhalf,0);
lhalf[k] = c/2 + '0';
k++;
}
}
else
{
if (prison == 1)
{
int c;
c = a - 1;
if ( c%2 != 0)
Down(fp1,fp2,lhalf,rhalf,0);
lhalf[k] = c/2 + '0';
k++;
}
else
{
if ( a%2 != 0)
Down(fp1,fp2,lhalf,rhalf,0);
lhalf[k] = a/2 + '0';
k++;
}
}
break;
}
if (ten == 1)
{
if (prison == 1)
{
if (a - b == 0)
{
lhalf[k] = '9';
rhalf[l] = b + '0';
k++; l++;
}
else if (a - b == -1)
{
lhalf[k] = '9';
rhalf[l] = b + '0';
ten = 0;
k++; l++;
}
else
{
Down(fp1,fp2,lhalf,rhalf,0);
}
}
else
{
if (a - b == 1)
{
lhalf[k] = '9';
rhalf[l] = (b + 1) + '0';
prison = 1;
k++; l++;
}
else if ( a - b == 0)
{
lhalf[k] = '9';
rhalf[l] = (b + 1) + '0';
ten = 0;
prison = 1;
k++; l++;
}
else
{
Down(fp1,fp2,lhalf,rhalf,0);
}
}
}
else
{
if (prison == 1)
{
if (a - b == 0)
{
lhalf[k] = b + '/';
rhalf[l] = '0';
ten = 1;
prison = 0;
k++; l++;
}
else if (a - b == -1)
{
lhalf[k] = b + '/';
rhalf[l] = '0';
ten = 0;
prison = 0;
k++; l++;
}
else
{
Down(fp1,fp2,lhalf,rhalf,0);
}
}
else
{
if (a - b == 0)
{
lhalf[k] = b + '0';
rhalf[l] = '0';
k++; l++;
}
else if (a - b == 1)
{
lhalf[k] = b + '0';
rhalf[l] = '0';
ten = 1;
k++; l++;
}
else
{
Down(fp1,fp2,lhalf,rhalf,0);
}
}
}
if(k == current_size_k - 1)
{
current_size_k += len_max;
lhalf = (char *)realloc(lhalf, current_size_k);
}
if(l == current_size_l - 1)
{
current_size_l += len_max;
rhalf = (char *)realloc(rhalf, current_size_l);
}
i++; j--;
}
lhalf[k] = '\0';
rhalf[l] = '\0';
MergePrint (lhalf,rhalf);
}
Down(fp1,fp2,lhalf,rhalf,3);
}
int Counter (FILE * fp)
{
int cntr = 0;
int c;
while ((c = fgetc(fp)) != '\n' && c != EOF)
{
cntr++;
}
return cntr;
}
void MergePrint (char * lhalf, char * rhalf)
{
int n,i;
printf("%s",lhalf);
n = strlen(rhalf);
for (i = n - 1; i >= 0 ; i--)
{
printf("%c",rhalf[i]);
}
printf("\n");
}
void Down(FILE * fp1, FILE * fp2, char * lhalf, char * rhalf, int n)
{
if (n == 0)
{
printf("0 \n");
}
else if (n == 1)
{
printf("Πρόβλημα κατά την διαχείρηση αρχείων τύπου txt\n");
}
fclose(fp1); fclose(fp2); free(lhalf); free(rhalf);
exit(2);
}
int SmallNums (FILE * fp1, int n)
{
fseek(fp1,0,0);
int M,N,Nr;
fscanf(fp1,"%i",&M);
if ( M == 66)
return 42;
N=M;
do
{
N--;
Nr = ReverseNum(N);
}while(N>0 && (N+Nr)!=M);
if((N+Nr)==M)
return N;
else
return 0;
}
int ReverseNum (int n)
{
int rev = 0;
while (n != 0)
{
rev = rev * 10;
rev = rev + n%10;
n = n/10;
}
return rev;
}
N + Nr加法中进行进位，将结果变成非回文数（即，如果您执行N + Nr加法而不传播进位，则最终会得到回文数字）。我不确定确切的算法是什么，但我确信，确定是否可以从G中删除某些具有特定属性的进位集，并以回文形式结束，您将能够获得答案。 - Michael Burr