求整数位数

C1 输入任意一个整数，求出它的位数

1. for 循环

#include<stdio.h>
#include<stdlib.h>
int main()
{
	int i,num;
	scanf_s("%d",&num);    
	for (i = 0; num ！= 0; i++)
	{
		num = num / 10;
	}
	printf("%d", i); 
	system("pause");
}

2. do while

int main()
{
	int i,num;
	i = 0;
	scanf_s("%d",&num);
	do
	{
		num = num / 10;
		i++;
	} while (num > 0);
	printf("%d", i);
	system("pause");
}

3. while

int main()
{
	int i,num;
	i = 0;
	scanf_s("%d", &num);
	while (num)
	{
		num /= 10;
		i++;
	}
	printf("%d", i);
	system("pause");
}

4. goto

int main()
{
	int i,num;
	i = 0;
	scanf_s("%d",&num);
A:	if (num)
	{
		num /= 10;
		i++;
		goto A;
	}
	printf("%d", i);
	system("pause");
}