可以使用C++ string 内置函数实现
#include <iostream>
#include <string>
using namespace std;
int main() {
string str;
getline(cin, str);
int whitespace = 0;
int digits = 0;
int chars = 0;
int others = 0;
// write your code here......
for (int i=0;i<=str.length();i++){
if (isalpha(str[i])){
chars++;
continue;
}
if (isdigit(str[i])){
digits++;
continue;
}
if (isspace(str[i])){
whitespace++;
continue;
}
else{
others++;
continue;
}
}
cout << "chars : " << chars
<< " whitespace : " << whitespace
<< " digits : " << digits
<< " others : " << others-1 << endl;
return 0;
}