Фрагмент "авс"

#include<stdio.h>
#include<conio.h>
#include<string.h>
main()
{
char *str;
int k=0,i=0;
FILE *FL;
clrscr();
FL=fopen("texst.txt","w");
printf("vvedite bukvy:");
scanf("%s",str);
fputs(str,FL);
fprintf(stderr,"vivoda v standartnii fail\n");
fclose(FL);
FL=fopen("texst.txt","r");
fgets(str,20,FL);
printf("str=%s",str);
fclose(FL);
 
while(i<strlen(str))
{
if(str[i]=='a')k++;
i++;
}

#include<stdio.h>
#include<string.h>
int main(){
 char *str= (char*)"fghfgfhfgfabchhkhhjhkabcyuyiuyuuiabcjkkjjkl";
 int i=0;
 FILE *FL;
 FL=fopen("texst.txt","w");
 fprintf(FL,"%s", str);
 fclose(FL);
 
 
 char* p;
 
 while ((p= strstr(str,"abc"))!=NULL) {
  str= p+++ 1;
  i++;
 }
 
 printf ("%d\n", i);
 getchar ();
}

#include <windows.h>
#include<stdio.h>
#include<string.h>
int main(){
 
 SetConsoleCP (1251);
 SetConsoleOutputCP (1251);
 
 
 
 char str_ [100];
 char* str= str_;
 
 printf ("Введи строку\n");
 gets (str_);
 int i=0;
 FILE *FL;
 FL=fopen("texst.txt","w");
 fprintf(FL,"%s", str);
 fclose(FL);
 
 
 char* p;
 
 while ((p= strstr(str,"abc"))!=NULL) {
  str= p+++ 1;
  i++;
 }
 
 printf ("%d\n", i);
 getchar ();
}