题解 | #字符串加解密#

#include <stdio.h>
#include <ctype.h>

//字母：位置+1；变换大小写--->变换大小写，位置-1
//数字：位置+1           --->位置-1

int main() {
    char arr1[1000],arr2[1000];
    scanf("%s",arr1);
    scanf("%s",arr2);
    int i=0;
    //en
    while(arr1[i]!='\0'){
        if(isalpha(arr1[i])){
            if(isupper(arr1[i])){
                if(arr1[i]=='Z'){
                    printf("a");
                }
                else{
                    printf("%c",tolower(arr1[i])+1);
                }
            }
            else{
                if(arr1[i]=='z'){
                    printf("A");
                }
                else{
                    printf("%c",toupper(arr1[i])+1);
                }
            }
        }
        else if(isdigit(arr1[i])){
            if(arr1[i]=='9'){
                printf("0");
            }
            else{
                printf("%c",arr1[i]+1);
            }
        }
        else{
            printf("%c",arr1[i]);
        }
        i++;
    }
    printf("\n");
    
    //de
    i=0;
    while(arr2[i]!='\0'){
        if(isalpha(arr2[i])){
            if(isupper(arr2[i])){
                if(arr2[i]=='A'){
                    printf("z");
                }
                else{
                    printf("%c",tolower(arr2[i])-1);
                }
            }
            else{
                if(arr2[i]=='a'){
                    printf("Z");
                }
                else{
                    printf("%c",toupper(arr2[i])-1);
                }
            }
        }
        else if(isdigit(arr2[i])){
            if(arr2[i]=='0'){
                printf("9");
            }
            else{
                printf("%c",arr2[i]-1);
            }
        }
        else{
            printf("%c",arr2[i]);
        }
        i++;
    }    

    return 0;
}