#include<iostream> #include<conio.h> #include<ctype.h> #include<stdio.h> using namespace std; int main() { FILE *in, *op; int key; int t1; char c; int ope; in = fopen("anip.txt","r"); op = fopen("anop.txt","w"); cout<<"\n What do you want to perform:"; cout<<"\n 1. Encryption"; cout<<"\n 2. Decryption"; cin>>ope; cout<<"\n Enter Key:"; cin>>key; if(ope == 1) //Encryption while(!feof(in)) { c = fgetc(in); if(c==-1) break; if(isupper(c)) { t1 = (int) c-(int) 'A'; t1 = (t1+key)%26; t1 = t1 + (int) 'A'; fputc((char) t1,op); } else if(islower(c)) { t1 = (int) c-(int) 'a'; t1 = (t1+key)%26; t1 = t1 + (int) 'a'; fputc((char) t1,op); } else{ fputc(c,op); } } else //decryption while(!feof(in)) { c = fgetc(in); if(c==-1) break; if(isupper(c)) { t1 = (int) c-(int) 'A'; t1 = (t1-key+26)%26; t1 = t1 + (int) 'A'; fputc((char) t1,op); } else if(islower(c)) { t1 = (int) c-(int) 'a'; t1 = (t1-key+26)%26; t1 = t1 + (int) 'a'; fputc((char) t1,op); } else{ fputc(c,op); } } //ending fclose(in); fclose(op); cout<<"\n Done"; getch(); return 0; }
Input Output for Encryption
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Input Output for Decryption
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Please explain the given solved program.