数，各位上的数最大值和最小值的乘积

#include <iostream>#include <cstdio>#include <string.h>using namespace std;int maxminmul(char *str){    int maxn,minn ;    maxn = -1;    minn = 10;    int len = strlen(str);    for(int i=0 ; i<len ; i++)    {        if((str[i] - '0') > maxn )            maxn = str[i]-'0';        if((str[i] - '0') < minn )            minn = str[i] -'0';    }    while(maxn*minn >= 10)    {        int mul = maxn * minn ;        maxn = mul / 10;        minn = mul % 10;    }    return maxn*minn;}int main(){    char str[110];    while(scanf("%s",str) == 1)    {        printf("%d\n",maxminmul(str));    }    return 0;}