字符串练习14_大小写字母互换

/*Name: 14_大小写字母互换Copyright: Author: Date: 01-09-17 17:06Description: 14_大小写字母互换查看 提交 统计 提问总时间限制: 1000ms 内存限制: 65536kB描述把一个字符串中所有出现的大写字母都替换成小写字母，同时把小写字母替换成大写字母。输入输入一行：待互换的字符串。输出输出一行：完成互换的字符串（字符串长度小于80）。样例输入If so, you already have a Google Account. You can sign in on the right. 样例输出iF SO, YOU ALREADY HAVE A gOOGLE aCCOUNT. yOU CAN SIGN IN ON THE RIGHT. */#include <iostream>#include <cstdio>#include <cstring>  using namespace std;    const int N = 81;  char S[N];   char *A="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";char *B="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";char L[255];   int main()   {  for (int i=0; A[i]!='\0'; i++)//获取转化关系表 {L[A[i]] = B[i];}  gets(S);      for (int i=0; S[i]!='\0'; i++)      {  if (isalpha(S[i]))        cout << L[S[i]];        else        cout << S[i];    }      cout << endl;        return 0;     }