题目链接:http://bailian.openjudge.cn/practice/3250
# include <stdio.h> int main() { int i,j,k,t; char str[1024]; scanf("%s",str); for(i=0,j=0;str[i]!='\0';i++) { if((str[i]>='a'&&str[i]<='z')||(str[i]>='A'&&str[i]<='Z')) { str[j]=str[i]; j++; } } for(i=0;i<j;i++) for(k=0;k<j-i-1;k++) { if(str[k]>str[k+1]) { t=str[k]; str[k]=str[k+1]; str[k+1]=t; } } for(i=0;i<j;i++) printf("%c",str[i]); printf("\n"); return 0; }