c - Writing and reading from a file and sort them in ascending order -

#include<stdio.h> void sort(int *p, int size) {   int i, j;   (i = 0; < size - 1; ++i)   {     (j = 0; j < size - - 1; ++j)     {       if (p[j] > p[j + 1])       {         int temp;         temp = p[j];         p[j] = p[j + 1];         p[j + 1] = temp;       }     }   } }  void createtestfile() {   file *f1;   f1 = fopen("program.txt", "w");   fprintf(f1, "6#this comment\n");   fprintf(f1, "3#this comment\n");   fprintf(f1, "7#this comment\n");   fprintf(f1, "2\n"); }  void readtestfile() {   file *fp;   char buff[1024];   int value;    int number_of_lines;   fp = fopen("program.txt", "r");     {     fgets(buff, 1024, fp);     fscanf(fp, "%d", &value);     number_of_lines++;     buff[number_of_lines] = value;   } while (fp != eof);    sort(buff, number_of_lines);    int i;   (i = 1; < number_of_lines; i++)   {     printf("value %d", buff[i]);   } }  int main() {   createtestfile();   readtestfile();   return 0; } 

i writing string file. later reading integers file , sort them in ascending order. using fgets reading line line file , have problem in reading integers file.

you missing close file after having written it.

due content propably written when application end, because clsoed implicitly.

add

fclose(f1)  

after last fprintf() in createtestfile().

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secondly when reading file should decide whether use fgets() of fscanf() read in data.

or can switch reading file directly using fscanf() sscanf() "string" read using fgets().

to replace

fscanf(fp, "%d", &value); 

with

sscanf(buff, "%d", &value); 

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thirdly makes no sense try write scanned in buff buff, @ least because overwriting buff in next round of read-loop.

also pass buff sort() should make compiler yell out loud warning.

initialise loop counter number_of_lines 0and use integer array store values scanned out of file's content. can pass sort().