Python的哦~

x=input()
s=0
for i in x:
    s+=int(i)
print(s)

#include <iostream>
#include <cmath>
using namespace std;
int y=0;
int main()
{
  long long x,n;
  cin>>x;



     while(x>0)
  {
       n=x%10;
       y+=n;
      x=x/10;

  }
 
  cout<<y;

 
  
  return 0;
}

不必分离各位数字，将输入的字符串形式逐位扫过就可以

num=input()
ans=0
for i in num:
    ans+=int(i)
print(ans)

#include <iostream>

using namespace std;

int main()
{
    long long a,sum=0;
    cin>>a;
    while(a){
        sum=sum+a%10;
        a=a/10;
    }
    cout<<sum<<endl;
    return 0;
}

s=0 a=input() for i in a: i=int(i) s=s+i print(s) 好人一生平凶