入门C语言求来教教我！

Question

Answer 1

#include <stdio.h>
int main()
{
char s[20]={0};
int i;
gets(s);
while(s[i] != '\0'){
if( ( s[i]>='a' && s[i]<='v') || (s[i]>='A' && s[i]<='V'))
s[i] += 4;
else if ( s[i]>'v' && s[i]<='z' )
s[i] = 'a' + s[i] - 'w';
else if(s[i]>='V' && s[i]<='Z')
s[i] = 'A' + s[i] - 'W';
else{printf("error\n");return 0;}
i++;
}
printf("%s\n",s);
return 0;
}