设计程序给英文句子加密

Question

当内容为26字母时，密文为其后第三个字母，如a-d。若为其他字符则不变

Answer 1

#include<stdio.h>
char a[200];
int main() {
    int len = 0;
    char ch;
    while((ch = getchar()) != '\n') {
        if(ch >= 'a' && ch <= 'z') {
            ch = ch + 3;
            if(ch > 'z') ch = ch - 26;
        } else if(ch >= 'A' && ch <= 'Z') {
            ch = ch + 3;
            if(ch > 'Z') ch = ch - 26;
        }
        a[len++] = ch;
    }
    printf("%s", a);
    return 0;
}