有一行电文,已按下面规律译成密码；
 A -- Z  a -- z
 B -- Y  b -- y
 C -- X  c -- x
  、
  、
  、
  、
  、

程序源码就不写了，方法是让一个变量记录第一个字母，最后一个字母为第一个字母+26并让另一个变量值向他，然后再设一个用于交换的变量，头变量做自加，尾变量做自减，进行交换，楼主动动脑筋自己写源码。

写算法就得了。

#include <stdio.h>
main()
{
    char c1[26]={a,b,cd,e,f,g,h,i,j,kl,m,n,o,p,q,r,s,t,u,v,w,x,y,z};
    char c2[]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,YZ};
    int i,j;
    for(i=1;i<=26;i++)
    {
              if(c1<='z'&&c1>='a')
                {    int temp;
                     temp=c[i];
                    c1[i]=c[26-i];
                    c[26-i]=temp;
                    printf("%c",c1[i]);
                }
     }
    for(i=1;i<=26;i++)
    {
              if(c1<='z'&&c1>='a')
                {    int temp;
                     temp=c[i];
                    c1[i]=c[26-i];
                    c[26-i]=temp;
                    printf("%c",c1[i]);
                }
     }
for(j=1;j<=26;j++)
    {
              if(c2<='Z'&&c2>='A')
                {    int temp;
                     temp=c2[j];
                    c2[j]=c2[26-j];
                    c2[26-j]=temp;
                    printf("%c",cj[j]);
                }
     }

}应该差不多就试 这个意思我也是菜鸟

貌似就用到tolower和islower这2个函数...

我也是初学者我只想到了
#include <stdio.h>
void main()
{
    char c,a;
    while((c=getchar())!='\n')
    {
        if((c>='a'&&c<='z')||(c>='A'&&c<='Z'))
            if(c<='Z')
            {
                a=c-64;
            switch(a)
            {
            case 26: c='A';break;
            case 25: c='B';break;
            case 24: c='C';break;
            case 23: c='D';break;
            case 22: c='E';break;
            case 21: c='F';break;
            case 20: c='G';break;
            case 19: c='H';break;
            case 18: c='I';break;
            case 17: c='G';break;
            case 16: c='K';break;
            case 15: c='L';break;
            case 14: c='M';break;
            case 13: c='N';break;
            case 12: c='O';break;
            case 11: c='P';break;
            case 10: c='Q';break;
            case 9: c='R';break;
            case 8: c='S';break;
            case 7: c='T';break;
            case 6: c='U';break;
            case 5: c='V';break;
            case 4: c='W';break;
            case 3: c='X';break;
            case 2: c='Y';break;
            case 1: c='Z';break;
            }
            }
        else
        {
            a=c-96;
            switch(a)
            {
            case 26: c='a';break;
            case 25: c='b';break;
            case 24: c='c';break;
            case 23: c='d';break;
            case 22: c='e';break;
            case 21: c='f';break;
            case 20: c='g';break;
            case 19: c='h';break;
            case 18: c='i';break;
            case 17: c='g';break;
            case 16: c='k';break;
            case 15: c='l';break;
            case 14: c='m';break;
            case 13: c='n';break;
            case 12: c='o';break;
            case 11: c='p';break;
            case 10: c='q';break;
            case 9: c='r';break;
            case 8: c='s';break;
            case 7: c='t';break;
            case 6: c='u';break;
            case 5: c='v';break;
            case 4: c='w';break;
            case 3: c='x';break;
            case 2: c='y';break;
            case 1: c='z';break;
            }
        }
        printf("%c\n",c);
    }
}

代码如下，仅供参考：
#include<iostream>
#include<string>
using namespace std;
int main()
{
 int i,l;
 char str[100];
 cout<<"请输入电文："<<endl;
 cin.get (str,100);
 l=strlen(str);
 for(i=0;i<l;i++)
 {
  if(str[i]>='a'&&str[i]<='z')
   str[i]=(str[i]-'a'+25)%26+'a';
  if(str[i]>='A'&&str[i]<='Z')
   str[i]=(str[i]-'A'+25)%26+'Z';
 }
 cout<<"译文为："<<endl;
 cout<<str<<endl;
 return 0;
}

switch(grade)
  {
   case 'A':
    acount++;   
    break;
   case 'B':
    bcount++;
    break;
   case 'C':
    ccount++;
    break;
  case 'D':
    dcount++;
    break;
  case 'E':
    ecount++;
    break;
  case 'F':
    fcount++;
    break;
  case 'W':
    wcount++;
    break;
  case 'I':
    icount++;
    break;
  default:
    cout << "error input" << endl;
    break;
  }

 0

都是高手

类似编写加密问题的程序、。。。呵呵、。。