C :

#include <stdio.h>
int main()
{
    char s[200];
    int i,n=0,flag=1;
    gets(s);
    for(i = 0; s[i]; i ++)
    {
        if(flag == 1)
        {
            if(s[i] != ' ')
            {
                n++;
                flag = 0;
            }
        }
        else if(s[i] == ' ')
            flag = 1;
    }
    printf("%d\n", n);
    return 0;
}

C++ :

#include <iostream>
#include <cstring>
using namespace std;

int main(){
	char s[1000]; 
	char w[1000];
	int i,j,k,c = 0;
	gets(s);
	k = 0;
	for(i = 0;i < strlen(s) - 1;i++){ 
		if(s[i] != ' '){
			w[k] = s[i];
			k++;
			if(s[i + 1] == ' ' || i + 1 == strlen(s) - 1){
				c++;
				w[k] = '\0';
				k = 0; 
			} 
		}
	}
	cout<<c;
}

Java :

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
public class Main{
	public static void main(String[] args) {
		Scanner scanner=new Scanner(System.in);
		String str=scanner.nextLine();
		String[] strArray=str.split(" ");
		List list=new ArrayList();
		for(int i=0;i<strArray.length;i++){
			if("".equals(strArray[i])){
			}else{
				list.add(strArray[i]);
			}
		}
		System.out.println(list.size());
	}
}

Python :

str1=input()
l = str1.split(' ')
s=0
for i in l:
    if len(i)!=0:
        s+=1
print(s)