C++ Note

1.write file

void outputFile(long time){
　　char buf[128];
　　int n=sprintf(buf,"%d",time); //write the content to buffer first!
　　buf[n]=0;
　　FILE *stream;
　　stream= fopen( "./time.txt", "w+b" );
　　fwrite(buf, 1,n, stream );　
　　fclose(stream);
}

  fwrite(buf, 1,n, stream );

　　buf: the content to write

　　1:the size of write per operation

　　n:the size of content