C :

#include<stdio.h>

main()

{

    char c;                                     /*定义c为字符型*/

    int letters = 0, space = 0, digit = 0;    /*定义letters、space、digit、others、四个变量为基本整型*/
    while ((c = getchar()) != '#')                      /*当输入的不是#时执行while循环体部分*/
    {
        if (c >= 'a' && c <= 'z')

            letters++;                              /*当输入的是英文字母时变量letters加1*/

        else

            if (c >= 'A' && c <= 'Z')

                space++;                            /*当输入的是空格时变量space加1*/

        else

            if (c >= '0' && c <= '9')

                digit++;                            /*当输入的是数字时变量digit加1*/

    }

    printf("%d %d %d",space,letters,digit);    /*将最终统计结果输出*/

}

C++ :

#include<iostream>
using namespace std;

int main(){
	
	int a,b,c;
	a=0;
	b=0;
	c=0;
	
	char x;

	x=getchar();
	while(x!='#'){
		if(x>='A' && x<='Z')
			a++;
			
		if(x>='a' && x<='z')
			b++;
			
		if(x>='0' && x<='9')
			c++;
			
		x=getchar();
	}
	cout<<a<<" "<<b<<" "<<c<<endl;
	
}

Python :

str = input('')
a = 0
b = 0
c = 0
for i in str:
    if i>='A' and i<='Z':
        a += 1
    if i>='a' and i<='z':
        b += 1
    if i>='0' and i<='9':
        c += 1
print(a,b,c)