单表置换加密与解密简单实现

加密程序

#include 
#include 
#include 
using namespace std;

int main(){
        freopen("SingleTable1.txt","r",stdin);
        freopen("SingleTable2.txt","w",stdout);
        string s;
        string t1 = "ILOVEMYCUNTRABDFGHJKPQSWXZ";
        string t2 = "ilovemycuntrabdfghjkpqswxz";

        while(getline(cin,s)){
                for(int i=0;iif(s[i]>='a' && s[i]<='z'){
                                printf("%c",t2[s[i]-97]);
                        }
                        else if(s[i]>='A' && s[i]<='Z'){
                                printf("%c",t1[s[i]-65]);
                        }
                        else{
                                cout << s[i];
                        }
                }
                cout << endl;
        }
        fclose(stdin);//关闭重定向输入
        fclose(stdout);//关闭重定向输出
        return 0;
}

解密程序

#include

int main(){
    char table1[] = "MNHOEPQRASTBFJCUVLWKIDXYGZ";
    char table2[] = "mnhoepqrastbfjcuvlwkidxygz";

    FILE *fp = fopen("SingleTable2.txt", "rt");
    FILE *res = fopen("SingleTable3.txt", "wt+");
    char ch;
    int k = 3;


    if(fp == NULL)
        printf("Cannot open file\n");
    if(res == NULL)
        printf("Cannot open file\n");
    ch = fgetc(fp);
    while(ch != EOF){
        if(ch >= 65 && ch <= 90){
                fputc(table1[ch-'A'], res);
        }
        else if(ch >= 97 && ch <= 122){
                fputc(table2[ch-'a'], res);
        }
        else
                fputc(ch ,res);

        ch = fgetc(fp);
    }
    fclose(fp);
    fclose(res);
}

待加密文本

GYPQJLRQGPYLJRGQYPL
GQYPRGQPYJRGQYPGY
mj O lezi e hvieq
wpvkn vjg gpf qh yqtnf

加密后文本

YXFGNRHGYFXRNHYGXFR
YGXFHYGFXNHYGXFYX
an D rezu e cqueg
sfqtb qny yfm gc xgkbm