纯C
懒得细分,直接128 hash
#include <stdlib.h> #include <stdio.h> #include <string.h> int main() { char str[1025] = {'\0'}; while(scanf("%s", str) != EOF) { int flag[128] = {0}; char *pstr = str; while(*pstr != '\0') { flag[(int)*pstr] = 1; pstr++; } for(int i=0; i<128; i++) { if(flag[i]) { pstr = str; while(*pstr != '\0') { if((int)*pstr == i) printf("%c", *pstr); pstr++; } } } printf("\n"); } return 0; }