void f(char input[],char output[])

{

bool flag

int i=0

while (input[i]!='\0')

{

flag=true

for (int j=0j<=25j++)

{

if (input[i]==a[j])

{

flag=false

output[i]=a[(j+1)%26]

break

}

else if (input[i]==A[j])

{

flag=false

output[i]=A[(j+1)%26]

break

}

}

if (flag==true)

{

output[i]=input[i]

}

i++

} // 将最后一个 '\0' 赋值给结果，表示字符串

结束

output[i]=input[i]

#include<stdio.h>

#include<string.h>

void main ()

{

char str[100]

char str1[100]

printf("输入字符串:")

scanf("%s",&str)

int len

len=strlen(str)

for(int i=0i＜leni++)

{

str1[i]=(str[i]-97+3)%26+97

}

str1[len]='\0'

printf ("密文为:%s\n",str1)

#include <iostream>

#include <string>

using namespace std

int main()

{

    string code//储存初始字符串

    string d_code//加密后的字符串

    int i

    int n         //移位的个数

    cout<<"Enter the string "<<endl

    cin>>code

    cout<<"how many step do you want to move ?"<<endl

    cin>>n

    for(i=0i<code.size()++i)

    {

        if(int(code[i])>97)

        {

            if(int(code[i])+n>122)

              d_code[i]=int(code[i])+n-26

            else

                d_code[i]=int(code[i])+n

        }

        else if(int(code[i])+n>90)

            d_code[i]=char(int(code[i])+n-26)

        else

            d_code[i]=char(int(code[i]+n))

    }

    for(i=0i<code.size()++i)

    {

        cout<<d_code[i]

    }

    cout<<endl

    cout<<"Code = "<<code<<endl

    return 0