算法提高----递归倒置字符数组

#include <stdio.h>
#include <stdlib.h> 

void swap(char *str1,int start,int end){
    char temp;
    temp = str1[start];
    str1[start] = str1[end];
    str1[end] = temp;
}

void Reverse_And_Print(char *str1,int start,int end){
    if(start == end){
        printf("%s\n",str1);
        return;
    }
    else{
        swap(str1,start,end);
        printf("%s\n",str1);
        Reverse_And_Print(str1,start+1,end-1);
    }
}

int main(){
    char str[7];
    char *str1;
    int num,num1;
    while(scanf("%s",str)!= EOF){
        scanf("%d",&num); 
        scanf("%d",&num1);
        str1 = (char *)malloc(sizeof(char)*(num1+1));
        scanf("%s",str1);
        printf("%s %d\n",str,num);
        Reverse_And_Print(str1,0,num1-1);
    }
    return 0;
}