【那个r,a+等等是什么啊!55.要打开文件c:usertext.txt用于追加数据,正确的语句是().A:fp=fopen("c:turboc2abc.txt","r");B:fp=fopen("c:turboc2abc.txt","r");C:fp=fopen("c:turboc2abc.txt","a+");D:fp=fopen("c:turboc2abc.txt"】

　　那个r,a+等等是什么啊!

　　55.要打开文件c:usertext.txt用于追加数据,正确的语句是().

　　A:fp=fopen("c:turboc2abc.txt","r");

　　B:fp=fopen("c:turboc2abc.txt","r");

　　C:fp=fopen("c:turboc2abc.txt","a+");

　　D:fp=fopen("c:turboc2abc.txt","a+");