判斷是否為數字、字母

#include <bits/stdc++.h>
using namespace std;
#define nn "\n"

int main(){
    cout<<isdigit('1')<<nn;
    cout<<isdigit('a');

    cout<<nn<<"-----------------"<<nn;

    cout<<isalpha('a')<<nn;
    cout<<isalpha('1');
}

1
0
-----------------
2
0

isdigit(字元)若字元為數字，回傳true否則回傳flase

isalpha(字元)若字元為字母，回傳true否則回傳flase