#include <stdio.h>
#include <string.h>
int main(){
int i;
char s[85];
gets(s);
for(i=0;s[i]!='\0';i++){
if(s[i]>='a'&&s[i]<='z')
{
s[i]=(s[i]-'a'+1)%26+'a';
}
else if(s[i]>='A'&&s[i]<='Z'){
s[i]=(s[i]-'A'+1)%26+'A';
}
printf("%c",s[i]);
}
}
用<ctype.h>写
#include <stdio.h>
#include <string.h>
#include <ctype.h>
int main(){
int i;
char s[85];
gets(s);
for(i=0;s[i]!='\0';i++){
if(islower(s[i]))
{
s[i]=(s[i]-'a'+1)%26+'a';
}
else if(isupper(s[i])){
s[i]=(s[i]-'A'+1)%26+'A';
}
printf("%c",s[i]);
}
}