1. 如果文件存在则清空,然后向文件写入内容
#include <stdio.h>
void fac(int x){
static FILE *fp;
static flag=0;
if(flag==0){
fp=fopen("coordinate.txt","w+");
flag=1;
}else{
fp=fopen("coordinate.txt","a+");
}
fprintf(fp,"%d\n",x);
fclose(fp);
}
int main(){
int i;
for(i=10;i<20;i++)
fac(i);
return 0;
}