#include <stdio.h> (737)#include <string.h> int main() { char str[128] = {0}; char s; int count = 0; while(scanf("%c", &s) != EOF) { if(!str[s] && s > 32) { count++; str[s] = 1; } } printf("%d\n", count); return 0; } 这样更好理解一点