#include<stdio.h>

#include<stdlib.h>

#include<string.h>

int f_calc(int p_v1, char p_sign, int p_v2) {

 switch (p_sign) {

 case '+':

  return p_v1 + p_v2;

 case '-':

  return p_v1 - p_v2;

 case '*':

  return p_v1 * p_v2;

 case '/': //这个地方有一个致命的地方

  if (!p_v2) {

   return -1;

  }

  else {

   return p_v1 / p_v2;

  }

 }

}

 

void main() {

 FILE* l_fp_read = fopen("1.txt", "r");

 if (!l_fp_read) {

  printf("打开读文件失败!\n");

  system("pause");

  return;

 }

 int l_last_position = NULL;

 char l_read_line[50] = { NULL };

 char l_write_line[50] = { NULL };

 int * p_save = NULL;

 int l_count = NULL;

 while (!feof(l_fp_read)) {

  fgets(l_read_line, sizeof(l_read_line), l_fp_read);

  int l_this_position = ftell(l_fp_read);

  if (l_this_position != l_last_position) {

   l_last_position = l_this_position;

   int l_v1, l_v2;

   char l_sign;

   int l_result;

   sscanf(l_read_line, "%d%c%d=", &l_v1, &l_sign, &l_v2);

   l_result = f_calc(l_v1, l_sign, l_v2);

   sprintf(l_write_line, "%d%c%d=%d\n", l_v1, l_sign, l_v2, l_result);

   //在C语言中,只要是系统内置的函数,如果里面包含scanf这个关键字.

   //你一定要使用取地址符号才能正常使用.

   l_count++;

   p_save = (int *)realloc(p_save, l_count*sizeof(int));

   int l_sizecount = strlen(l_write_line) + 1;

   p_save[l_count - 1] = (int)calloc(l_sizecount, sizeof(char));

   strcpy((char *)p_save[l_count - 1], l_write_line);

  }

 }

 FILE* l_fp_write = fopen("1.txt", "w");

 if (!l_fp_write) {

  printf("打开写文件失败!\n");

  system("pause");

  return;

 }

 for (size_t i = 0; i < l_count; i++) {

  fputs((char *)p_save[i], l_fp_write);//ctrl+J

  free((char *)p_save[i]);

 }

 free(p_save);

 fclose(l_fp_read);

 printf("\n自动答题工作完成\n");

 system("pause");

 

#include<stdio.h>

#include<stdlib.h>

#include<string.h>

int count (int one, int tow, char symbol) {

switch (symbol) {

case '+':

return one + tow;

case '-':

return one - tow;

case '*':

return one * tow;

case '/':

if (!tow) {

return 0;

}

else { return one / tow; }

}

}

 

 

 

 

 

void main() {

FILE*read = fopen("1.txt", "r");

if (!read) {

printf("文件为空");

system("pause");

return;

}

int kong = NULL;

char pp[50] = { NULL };

char bb[50] = { NULL };

int *shenqing=NULL;

int counter = NULL;

while (!feof(read)) {

fgets(pp, sizeof(pp), read);

int shaomiao = ftell(read);

if (shaomiao != kong) {

int one; int tow; char symbol;

sscanf(pp, "%d%c%d=",&one, &symbol, &tow);

int result=count(one, tow, symbol);

sprintf(bb, "%d%c%d=%d\n", one, symbol, tow, result);

counter++;

shenqing = (int*)realloc(shenqing, counter*sizeof(int));

int cc = strlen(bb)+1;//加是因为1+1=\n\NULL,NULL是结束标志

shenqing[counter - 1] = (int)calloc(cc, sizeof(char));

strcpy((char*)shenqing[counter - 1], bb);

}

 

}

FILE*write = fopen("1.txt", "w");

for (size_t i = 0; i < counter; i++)

{

fputs((char*)shenqing[i], write);

free((char*)shenqing[i]);

}

free(shenqing);

fclose(read);

system("pause");

}