文件操作

#include<stdio.h>
#include<stdlib.h>
int main(){
char a[5]={'1','2','3','3'};
int cnt=0;
char x,ch;
FILE * fp;
char filename[10];
printf("wen jian \n");
scanf("%s",filename);
getchar();
if((fp=fopen(filename,"w"))==NULL){
printf("no\n");
exit(0);
}
fwrite(a,sizeof(a),1,fp);
fclose(fp);
if((fp==fopen(filename,"r"))==NULL){
printf("no2\n");
exit(0);
}
scanf("%c",&x);
while(!feof(fp)){
ch=fgetc(fp);
if(ch==x)cnt++;
}
printf("%d",cnt);
return 0;
}