binaryfiles - Read/Write int Binary File in C error -

i facing error reading/writing binary file in c. issue is: - write int (e.g. 2) file using fwrite - try read int file using fread - when read it, doesn't come out 2, rather long number e.g. 967899906 or 2071332354 or 1030372866 (always different).

i write binary file in c this:

file * writefile = fopen("test.bin","wb");  //test int vars int test1 = 1; int test2 = 2; int test3 = 3;  //writing ints binary file fwrite(&test1,1,1, writefile); fwrite(&test2,1,1, writefile); fwrite(&test3,1,1, writefile);  fclose(writefile); 

i read file this:

file *readfile = fopen("test.bin","rb"); int data; while(fread(&data,1,1, readfile)==1){    printf("%d", data); //here output random number } fclose(readfile); 

fwrite wants, second parameter, size of data write, in case sizeof(int)

same thing fread

#include <stdio.h>  int main(void) {      file * writefile = fopen("test.bin","wb");       if (writefile != null)      {          //test int vars          int test1 = 1;          int test2 = 2;          int test3 = 3;           //writing ints binary file          fwrite(&test1,sizeof(test1),1, writefile);          fwrite(&test2,sizeof(test2),1, writefile);          fwrite(&test3,sizeof(test3),1, writefile);           fclose(writefile);      }      else      {          perror("error opening file write: ");          return 1;      }        file *readfile = fopen("test.bin","rb");      if (readfile != null)      {          int data;          while(fread(&data,sizeof(data),1, readfile)==1){             printf("%d\n", data);          }          fclose(readfile);      }      else      {          perror("error opening file read: ");          return 1;      }      return 0; } 

hint: test if fopen succeed.

edit

to use 1 byte variable, commented, use uint8_t variables

#include <stdio.h> #include <stdint.h>  int main(void) {      file * writefile = fopen("test.bin","wb");       if (writefile != null)      {          //test int vars          uint8_t test1 = 1;          uint8_t test2 = 2;          uint8_t test3 = 3;           //writing ints binary file          fwrite(&test1,sizeof(test1),1, writefile);          fwrite(&test2,sizeof(test2),1, writefile);          fwrite(&test3,sizeof(test3),1, writefile);           fclose(writefile);      }      else      {          perror("error opening file write: ");          return 1;      }        file *readfile = fopen("test.bin","rb");      if (readfile != null)      {          uint8_t data;          while(fread(&data,sizeof(data),1, readfile)==1){             printf("%d\n", data);          }          fclose(readfile);      }      else      {          perror("error opening file read: ");          return 1;      }      return 0; }