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49 lines
936 B
49 lines
936 B
/*
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* pr_13.c
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*
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* Created on: Jun 12, 2013
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* Author: delmadord
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*/
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#include <stdio.h>
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#define MESSAGE_LEN 100
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void caesar_encrypt(char *message, int shift);
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int read_line(char str[], int n);
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// Caesar cipher
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int main(void) {
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char message[MESSAGE_LEN + 1];
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int shift;
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printf("Enter message to be encrypted: ");
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read_line(message, MESSAGE_LEN);
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printf("Enter shift amount: ");
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scanf("%d", &shift);
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caesar_encrypt(message, shift);
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printf("Encrypted message: %s", message);
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return 0;
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}
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void caesar_encrypt(char *message, int shift) {
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while (*message) {
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if (*message >= 'A' && *message <= 'Z')
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*message = ((*message - 'A') + shift) % 26 + 'A';
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else if (*message >= 'a' && *message <= 'z')
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*message = ((*message - 'a') + shift) % 26 + 'a';
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message++;
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}
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}
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int read_line(char str[], int n) {
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int ch, i = 0;
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while ((ch = getchar()) != '\n')
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if (i < n)
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str[i++] = ch;
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str[i] = '\0';
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return i;
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}
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