勝手に作り変えてやんよ

#include<stdio.h>
int main(void){
FILE *fin,*fout;
char stn[FILENAME_MAX],c;
printf("filename: ");
scanf("%s",stn);
if((fin=fopen(stn,"r"))==NULL)return (-1);
fout=fopen("bou.txt","w");
while((c=getc(fin))!=EOF) {
if(c=='a'||c=='o'||c=='e'||c=='i'||c=='u')
fputc('-',fout);
else
fputc(c,fout);
}
fclose(fin);
fclose(fout);
return 0;}