编程实现(整数位数)：用户输入一个非负整数，程序在屏幕上输出该数的位数，如果是负数直接输出0。

num = int(input("请输入一个非负整数："))
if num < 0:
    print(0)
else:
    count = 0
    while num != 0:
        count += 1
        num //= 10
    print("该数的位数为：", count)

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int num = scanner.nextInt();
        if (num < 0) {
            System.out.println(0);
        } else {
            int count = 0;
            while (num != 0) {
                count++;
                num /= 10;
            }
            System.out.println("该数的位数为："+count);
        }
        scanner.close();
    }
}

#include <iostream>

using namespace std;

int main() {
    int num;
    cout << "请输入一个非负整数：";
    cin >> num;
    if (num < 0) {
        cout << 0 << endl;
    } else {
        int count = 0;
        while (num != 0) {
            count++;
            num /= 10;
        }
        cout << "该数的位数为：" << count << endl;
    }
    return 0;
}

#include <stdio.h>

int main() {
    int num;
    printf("请输入一个非负整数：");
    scanf("%d", &num);
    if (num < 0) {
        printf("0\n");
    } else {
        int count = 0;
        while (num != 0) {
            count++;
            num /= 10;
        }
        printf("该数的位数为：%d\n", count);
    }
    return 0;
}