编程统计一条英文句子中字母的个数和非字母的个数，在主程序中实现输入输出。（c++）

#include #include #include int main() { int i; unsigned letters = 0; unsigned spaces = 0; unsigned digits = 0; unsigned others = 0; char line[256]; printf("Enter a line of words: \n"); gets(line); for(i = 0; i <