编写一个C函数,将”I am from shanghai ”倒置为”shanghai from am I”,及将句子中的单词位置倒置,而不改变单词内部结构.

#include <stdio.h>#define N 50int i=0;void input(char c[]){//int i=0;char s;for(;(s=getchar())!='\n';i++){c[i]=s;}c[i]='\0';}int main(){int j,k,c=0,j_c=0,jk=0,j_k=0;char str[N],str_new[N];printf("input a string:\n");input(str);j_c=i;for(j=i;j>0;j--){//printf("%c",str[j]);if(str[j]==' '){//jk++;for(k=j+1;k<j_c;k++){str_new[c++]=str[k];}str_new[c++]=' ';j_c=j;}}if(j==0){for(k=0;k<j_c;k++){str_new[c++]=str[k];}}str_new[c]='\0';for(k=0;k<i;k++){printf("%c",str_new[k]);}printf("\n");    return 0;}