#include <stdio.h>#include <string.h>#define KEY 5 //偏移量/** 加密和解密字符串* 加密规则:字符串每个字符加上其在字符串中的位置再加上偏移量5成为新字符*/char * encrypt(char []);//加密字符串;*代表返回一个指针类型的变量char * dencrypt(char []);//解密字符串int main() {char password[50] = "Hello World!";encrypt(password);printf("%s\n", password);dencrypt(password);printf("%s\n", password);return 0;}char * encrypt(char password[]){int length = strlen(password);//不包括'\0'for (int i = 0; i < length; i++) {password[i] += (i+KEY);}return password;}char * dencrypt(char password[]){int length = strlen(password);for (int i = 0; i < length; ++i) {password[i] -=(i+KEY);}return password;}
输出: