我遇到问题让我的do / while循环正常运行。 这个程序在第一次复飞时运行良好,但是当我输入'y'时它询问我是否想要“告诉更多”程序只询问用户问题(不允许我输入字符串)然后cout声明。我究竟做错了什么?以及如何让它正常运作?
using namespace std;
int main()
{
int i, numspaces = 0;
char nextChar;
string trimstring;
string uc, rev;
string answer;
char temp;
cout << "\n\n John Acosta"
<<" Exercise 1\n"
<< "\n\n This program will take your string, count the number\n"
<< " of chars and words, UPPERCASE your string, and reverse your string.";
string astring;
do {
cout << "\n\nTell me something about yourself: ";
getline (cin, astring);
trimstring = astring;
uc = astring;
rev = astring;
for (i=0; i<int(astring.length()); i++)
{
nextChar = astring.at(i); // gets a character
if (isspace(astring[i]))
numspaces++;
}
trimstring.erase(remove(trimstring.begin(),trimstring.end(),' '),trimstring.end());
transform(uc.begin(), uc.end(),uc.begin(), ::toupper);
for (i=0; i<rev.length()/2; i++)
{
temp = rev[i];
rev[i] = rev[rev.length()-i-1];
rev[rev.length()-i-1] = temp;
}
cout << "\n\tYou Entered: " << astring
<< "\n\tIt has "<<trimstring.length()
<< " chars and "<<numspaces+1
<< " words."
<< "\n\tUPPERCASE: "<<uc
<< "\n\tReversed: "<<rev
<< "\n\n";
cout<<"\n\nwant to tell me more? Enter \"y\" for YES and \"n\" for NO\n\n";
cin>>answer;
cout<<"\n";
} while(answer == "y"); //contiue loop while answer is 'y'; stop when 'n'
{
cout <<"\n Thanks. Goodbye!\n"; //when loop is done
}
return 0;
}
答案 0 :(得分:4)
输入操作符>>
的工作原理如下:首先它跳过空格,如果有的话;然后它读取字符串直到它到达下一个空格,在你的情况下是'y'
之后的换行符。然后,此换行符会保留在流中,因此当您在循环开始处getline
时,您会在"y"
之后离开该换行符。
您可以使用ignore
功能删除它:
cout<<"\n\nwant to tell me more? Enter \"y\" for YES and \"n\" for NO\n\n";
cin>>answer;
std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
cout<<"\n";