题解 | #字符串加解密#

#include <stdio.h>
#include <string.h>

char insecret(char x);
char unsecret(char x);
int main()
{
    char willsecret[10001];
    char hadsecret[1001];
    while (scanf("%s", willsecret) != EOF)
    {
        scanf("%s", hadsecret);
        int len1 = strlen(willsecret);
        int len2 = strlen(hadsecret);

        for (int i = 0; i < len1; i++)
        {
            willsecret[i] = insecret(willsecret[i]);
        }
        for (int i = 0; i < len2; i++)
        {
            hadsecret[i] = unsecret(hadsecret[i]);
        }

        printf("%s\n", willsecret);
        printf("%s\n", hadsecret);
    }

    return 0;
}

char insecret(char x)
{
    char ret;
    if (x >= 'a' && x <= 'z')
        ret = (x - 'a' + 1) % 26 + 'A';
    else if (x >= 'A' && x <= 'Z')
        ret = (x - 'A' + 1) % 26 + 'a';
    else if (x >= '0' && x <= '9')
        ret = (x - '0' + 1) % 10 + '0';
    return ret;
}

char unsecret(char x)
{
    char ret;
    if (x >= 'a' && x <= 'z')
        ret = (x - 'a' - 1 + 26) % 26 + 'A';
    else if (x >= 'A' && x <= 'Z')
        ret = (x - 'A' - 1 + 26) % 26 + 'a';
    else if (x >= '0' && x <= '9')
        ret = (x - '0' - 1 + 10) % 10 + '0';
    return ret;
}