Title (1) answer

Because only one line of input, but can have spaces, so we must use getline () function.
Enter a string variable.

#include <iostream>
#include <string>
#include <cstring>
#include <cstdlib>

using namespace std;

int main()
{
    string s;
    getline(cin,s);
    int length;
    length=s.size();
    int sum=0;
    for(int i=0;i<length;i++)//遍历字符串
    {
        if(s[i]==' ')
            continue;
        else
            sum++;
    }
    cout<<sum<<endl;
    return EXIT_SUCCES;
}