#include <iostream>
using namespace std;
#define MaxSize 50
typedef char ElemType;
typedef struct {
char data[MaxSize];
int length;
} SqString;
SqString sqStr, matchStr;
void create(SqString &s, char cstr[]) {
int i = 0;
for (i = 0; cstr[i] != '\0'; i++) {
s.data[i] = cstr[i];
}
s.length = i;
}
void DestroyStr(SqString &s) {
}
void show(SqString s) {
int i;
if (s.length > 0) {
for (i = 0; i < s.length; i++) {
cout << s.data[i];
}
cout << endl;
}
}
SqString jiami(SqString p) {
int i = 0, j = 0;
SqString q; //接收加密对应的字符
for (i = 0; i <= p.length; i++) {
j = 0;
while (p.data[i] != sqStr.data[j] && j < sqStr.length) {
j++; //用j控制对应映射位置的字符
}
if (j >= sqStr.length)
q.data[i] = p.data[i];
else
q.data[i] = matchStr.data[j]; //将映射的字符赋给字符串q的数据
}
q.length = p.length;
return q;
}
SqString jiemi(SqString q) {
int i = 0, j;
SqString p; //接收解密对应的字符
for (i = 0; i <= q.length; i++) {
j = 0;
while (q.data[i] != matchStr.data[j] && j < matchStr.length) {
j++; //用j控制对应解密位置的字符
}
if (j >= matchStr.length)
p.data[i] = q.data[i];
else
p.data[i] = sqStr.data[j]; //将解密的字符赋给字符串q的数据
}
p.length = q.length;
return p;
}
int main() {
SqString jiami(SqString p); //函数声明
SqString jiemi(SqString q); //函数声明
SqString p, q;
char inputStr[MaxSize]; //存放输入的字符串
char sqChar[MaxSize] = "abcdefghijklmnopqrstuvwxyz"; //顺序字符串
char matchChar[MaxSize] = "ngzqtcobmuhelkpdawxfyivrsj"; //映射字符串
create(sqStr, sqChar);
create(matchStr, matchChar);
cout << "输入字符串:" << endl;
cin >> inputStr;
create(p, inputStr);
cout << "原文串:" << endl;
show(p);
q = jiami(p);
cout << "加密串:" << endl;
show(q);
p = jiemi(q);
cout << "解密串:" << endl;
show(p);
system("pause");
return 0;
}
1.1 实验目的
掌握串的应用算法设计。
1.2实验内容
一个文本串可用事先给定的字母映射表进行加密。例如,设字母映射表为:
a b c d e f g h i j k l m n o p q r s t u v w x y z
n g z q t c o b m u h e l k p d a w x f y I v r s j
则字符串“encrypt”被加密为“tkzwsdf”。编写一个程序exp4-4.cpp,将输入的文本串加密后输出,然后进行解密并输出。