taoyy.c

用替换算法编的一个加密程序

#include <stdio.h>
main() 
{ 
char M[200];
char C[200];
int i;
printf("please input character:\n");
gets(M);

for(i=0;M[i]!='\0';i++)
    if(M[i]=='A')
               C[i]=M[i]+10;
    else if(M[i]=='B')
               C[i]=M[i]+22;
    else if(M[i]=='C')
               C[i]=M[i]+19;
    else if(M[i]=='D')
               C[i]=M[i]+9;
    else if(M[i]=='E')
               C[i]=M[i]-2;
    else if(M[i]=='F')
               C[i]=M[i]+8;
    else if(M[i]=='G')
               C[i]=M[i]+8;
    else if(M[i]=='H')
               C[i]=M[i]+8;
    else if(M[i]=='I')
               C[i]=M[i]-1;
    else if(M[i]=='J')
               C[i]=M[i]+7;
    else if(M[i]=='K')
               C[i]=M[i]+7;
    else if(M[i]=='L')
               C[i]=M[i]+7;
    else if(M[i]=='M')
               C[i]=M[i]+13;
    else if(M[i]=='N')
               C[i]=M[i]+11;
    else if(M[i]=='O')
               C[i]=M[i]-6;
    else if(M[i]=='P')
               C[i]=M[i]-6;
    else if(M[i]=='Q')
               C[i]=M[i]-16;
    else if(M[i]=='R')
               C[i]=M[i]-14;
    else if(M[i]=='S')
               C[i]=M[i]-7;
    else if(M[i]=='T')
               C[i]=M[i]-15;
    else if(M[i]=='U')
               C[i]=M[i]-14;
    else if(M[i]=='V')
               C[i]=M[i]+1;
    else if(M[i]=='W')
               C[i]=M[i]-21;
    else if(M[i]=='X')
               C[i]=M[i]-3;
    else if(M[i]=='Y')
               C[i]=M[i]-19;
    else if(M[i]=='Z')
               C[i]=M[i]-6;


else if(M[i]=='a')
    C[i]=M[i]+10;
else if(M[i]=='b')
    C[i]=M[i]+22;
else if(M[i]=='c')
    C[i]=M[i]+19;
else if(M[i]=='d')
     C[i]=M[i]+9;
else if(M[i]=='e')
     C[i]=M[i]-2;
else if(M[i]=='f')
     C[i]=M[i]+8;
else if(M[i]=='g')
     C[i]=M[i]+8;
else if(M[i]=='h')
     C[i]=M[i]+8;
else if(M[i]=='i')
     C[i]=M[i]-1;
else if(M[i]=='j')
     C[i]=M[i]+7;
else if(M[i]=='k')
     C[i]=M[i]+7;
else if(M[i]=='l')
     C[i]=M[i]+7;
else if(M[i]=='m')
     C[i]=M[i]+13;
else if(M[i]=='n')
     C[i]=M[i]+11;
else if(M[i]=='o')
     C[i]=M[i]-6;
else if(M[i]=='p')
     C[i]=M[i]-6;
else if(M[i]=='q')
     C[i]=M[i]-16;
else if(M[i]=='r')
     C[i]=M[i]-14;
else if(M[i]=='s')
     C[i]=M[i]-7;
else if(M[i]=='t')
     C[i]=M[i]-15;
else if(M[i]=='u')
     C[i]=M[i]-14;
else if(M[i]=='v')
     C[i]=M[i]+1;
else if(M[i]=='w')
     C[i]=M[i]-21;
else if(M[i]=='x')
     C[i]=M[i]-3;
else if(M[i]=='y')
     C[i]=M[i]-19;
else if(M[i]=='z')
     C[i]=M[i]-6;

  printf("result is:\n%s\n",C);
getch();
}