输入一串字符，统计字母、数字、空格、其他字符的个数

#include <stdio.h>

int main()

{

char c;

int letter = 0, space = 0, digit = 0, other = 0;

printf("input a char line:");

c = getchar();

while (c != '\n')

{

 if (c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z')

  letter++;

 else if (c >= '0' && c <= '9')

  digit++;

 else if (c == ' ')

  space++;

 else

  other++;

 c = getchar();

}

printf("letter=%d digit=%d space=%d other=%d",letter,digit,space,other);

return 0;

}