c语言冒泡实现将一个字符串按照字典顺序输出

#include<stdio.h>
#include<string.h>
void main(){
char a[100];
gets(a);
int i,j,temp;
for(j=0;j<strlen(a);j++){
for (i = 0; i < strlen(a) - 1 - j; i++)
{
if(a[i] < a[i + 1])
{
temp = a[i];
a[i] = a[i + 1];
a[i + 1] = temp;
}
}

printf("%c",a[i]);
}
}