Replacing elements in an array - c

I have a problem thats giving me a huge ache.
This piece of code purpose is to fill up an array with integer values and at the same time defend against strings and etc....but it doesn't defend against duplicates, but tried I got to far as replacing the number with a new number for example
Enter 6 integers
1, 2, 2, 3, 4, 5
my code will let me replace that 2 at position 1 with another number. What I want it to do is not to repeat the same number again, for example please replace 2 at position 1. I dont want the user to enter 2 again... and I want to make it to double check the work the array if any repeating numbers exists thank you.
system("clear");
printf("\nEntering Winning Tickets....\n");
nanosleep((struct timespec[]){{1, 0}}, NULL);
system("clear");
char userInput[256];
char c;
int duplicationArray[6] = {-1, -1, -1, -1, -1, -1};
for (i = 0; i < 6; i++)
{
printf("\nPlease enter the %d winning ticket number!(#'s must be between 1-49): ", i+1);
fgets(userInput, 256, stdin);
if ((sscanf(userInput, "%d %c", &winningNumbers[i], &c) != 1 || (winningNumbers[i] <= 0) || winningNumbers[i] >= 50))
{
printf("\nInvalid Input.\n") ;
nanosleep((struct timespec[]){{0, 350000000}}, NULL);
system("clear");
i = i - 1;
}
}
for (i = 0; i < 6 - 1; ++i)
{
min = i;
for (j = i+1; j < 6; ++j)
{
if (winningNumbers[j] < winningNumbers[min])
min = j;
}
temp = winningNumbers[i];
winningNumbers[i] = winningNumbers[min];
winningNumbers[min] = temp;
}
for (i = 0; i < 6; i++)
{
if (winningNumbers[i] == winningNumbers[i+1])
{
duplicationArray[i] = i;
duplicationCounter++;
}
else
{
duplicationCounter--;
}
}
if (duplicationCounter > -6)
{
for (i = 0; i < 6; i++)
{
int j, min, temp;
min = i;
for (j = i+1; j < 6; ++j)
{
if (duplicationArray[j] > duplicationArray[min])
min = j;
}
temp = duplicationArray[i];
duplicationArray[i] = duplicationArray[min];
duplicationArray[min] = temp;
}
for (i = 0; i < 6; i++)
{
if (duplicationArray[i] == -1)
{
zeroCounter++;
}
}
int resize = (6 - zeroCounter)+1;
for (i = 0; i <= resize; i++)
{
if (duplicationArray[i] == -1)
{
i++;
}
else if (duplicationArray[i] != -1)
{
system("clear");
printf("\nDuplicated numbers has been dected in your array. ");
printf("\nPlease replace the number %d at postion %d with another number: ", winningNumbers[duplicationArray[i]], duplicationArray[i]);
fgets(userInput, 256, stdin);
if ((sscanf(userInput, "%d %c", &winningNumbers[duplicationArray[i]], &c) != 1 || (winningNumbers[i] <= 0) || winningNumbers[i] >= 50))
{
printf("\nInvalid Input.\n") ;
nanosleep((struct timespec[]){{0, 350000000}}, NULL);
system("clear");
i = i - 1;
}
}
}
duplicationCounter = 0;
for (i = 0; i < 6; i++)
{
if (winningNumbers[i] == winningNumbers[i+1])
{
duplicationArray[i] = i;
duplicationCounter++;
}
else
{
duplicationCounter--;
}
}
printf("%d, ", duplicationCounter);
}

#include <stdio.h>
#include <stdint.h>
#define DATA_SIZE 6
int main(void){
char userInput[256];
int inputNum, winningNumbers[DATA_SIZE];
uint64_t table = 0;
int i=0;
while(i<DATA_SIZE){
printf("\nPlease enter the %d winning ticket number!(#'s must be between 1-49): ", i+1);
fgets(userInput, sizeof(userInput), stdin);
if(sscanf(userInput, "%d", &inputNum) != 1 || inputNum <= 0 || inputNum >= 50)
continue;
uint64_t bit = 1 << inputNum;
if(table & bit)
continue;
table |= bit;
winningNumbers[i++] = inputNum;
}
for(i=0;i<DATA_SIZE;++i)
printf("%d ", winningNumbers[i]);
printf("\n");
return 0;
}

#include <stdio.h>
#include <stdlib.h>
#define DATA_SIZE 6
int inputNumberWithRangeCheck(const char *msg, const char *errMsg, int rangeStart, int rangeEnd){
char inputLine[256];
int n;
for(;;){
printf("%s", msg);
fgets(inputLine, sizeof(inputLine), stdin);
if(sscanf(inputLine, "%d", &n) != 1 || n < rangeStart || n > rangeEnd)
fprintf(stderr, "%s", errMsg);
else
return n;
}
}
int inputNumber(void){
return inputNumberWithRangeCheck(
"\nPlease enter the winning ticket number!(#'s must be between 1-49): ",
"Invalid Input.\n",
1,49);
}
int *inputArray(int *array, size_t size){
int i;
for(i=0;i<size;++i){
printf("\nInput for No.%d\n", i+1);
array[i] = inputNumber();
}
return array;
}
int **duplicateCheck(int *array, size_t size){
int **check, count;
int i, j;
check = malloc(size*sizeof(int*));
if(!check){
perror("memory allocate\n");
exit(-1);
}
//There is no need to sort the case of a small amount of data
//(Cost of this loop because about bubble sort)
for(count=i=0;i<size -1;++i){
for(j=i+1;j<size;++j){
if(array[i] == array[j]){
check[count++] = &array[i];
break;
}
}
}
check[count] = NULL;
if(count)
return check;
else {
free(check);
return NULL;
}
}
int main(void){
int winningNumbers[DATA_SIZE];
int **duplication;
int i, j;
inputArray(winningNumbers, DATA_SIZE);
while(NULL!=(duplication = duplicateCheck(winningNumbers, DATA_SIZE))){
for(i=0;i<DATA_SIZE;++i){
if(duplication[i]){
printf("\nyour input numbers : ");
for(j=0;j<DATA_SIZE;++j)
printf("%d ", winningNumbers[j]);
fprintf(stderr, "\nThere is duplicate. Please re-enter.\n");
*duplication[i] = inputNumber();
} else
break;
}
free(duplication);
}
for(i=0;i<DATA_SIZE;++i)
printf("%d ", winningNumbers[i]);
printf("\n");
return 0;
}

Related

Incorrect output using strcmp

I'm doing the day 8 of the 30 days of code in HackerRank and I am having a problem with strcmp.
The code asks the user for names of people and their numbers, then asks for other names, if a name wasn't entered before, then it outputs Not found, but if it was then it outputs the name and his number. But for some reason, the output only works in the last loop of the for statement.
Code:
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
typedef struct {
char name[100];
int number;
} phonebook;
int main() {
int n = 0;
do {
scanf("%i", &n);
} while (n < 1 || n > 100000);
int i = 0;
phonebook people[n];
for (i = 0; i < n; i++) {
scanf("%s %i", people[i].name, &people[i].number);
}
char othernames[n][100];
for (i = 0; i < n; i++) {
scanf("%s", othernames[i]);
}
for (i = 0; i < n; i++) {
if (strcmp(othernames[i], people[i].name) == 0) {
printf("%s=%i\n", people[i].name, people[i].number);
} else {
printf("Not found\n");
}
}
return 0;
}
You didn't find the othernames from the beginning to end to compare peopleevery time, so you need to replace
for (i = 0; i < n; i++) {
if (strcmp(othernames[i], people[i].name) == 0) {
printf("%s=%i\n", people[i].name, people[i].number);
}
else {
printf("Not found\n");
}
}
to
bool found = false;
for (i = 0; i < n; i++) {
for ( j = 0 ; j < n ; j++ ) {
if (strcmp(othernames[j], people[i].name) == 0) {
printf("%s=%i\n", people[i].name, people[i].number);
found = true;
}
}
}
if ( found == false ) printf("Not found\n");
The problem is othernames should just be an array of char, not a matrix. And for each othername entered, you must scan whole phonebook to find it or display Not found. As coded, you only test if the i-th othername typed happens to correspond to the i-th entry in the phone book.
Here is a modified version:
#include <stdio.h>
#include <string.h>
typedef struct {
char name[100];
int number;
} phonebook;
int main() {
int n = 0;
do {
if (scanf("%i", &n) != 1)
return 1;
} while (n < 1 || n > 100000);
phonebook people[n];
for (int i = 0; i < n; i++) {
if (scanf("%99s %i", people[i].name, &people[i].number) != 2)
return 1;
}
for (int i = 0; i < n; i++) {
char othername[100];
if (scanf("%99s", othername) != 1)
break;
int j;
for (j = 0; j < n; j++) {
if (strcmp(othername, people[j].name) == 0) {
printf("%s=%i\n", people[i].name, people[i].number);
break;
}
}
if (j == n) {
printf("Not found\n");
}
}
return 0;
}
Note that it is probably not a good idea to store phone numbers as int values. Better use a char array so an initial 0 is significant and to store longer numbers.

C program to insert elements into an array until user inputs a 0 or less number

I'm trying to make a C program to insert elements into an array until user inputs a 0 or less number, as the title says. But when I print the array out, it doesn't show the numbers I inputted. I have tried using a while as well as do-while loops but without success.
#include <stdio.h>
int main() {
int data[100];
int i;
for (i = 0; i < 100; i++) {
printf("Input your number:\n");
scanf("%d", &data[i]);
if (data[i] <= 0) {
break;
}
}
printf("Your array:");
int n = sizeof(data[i]);
for (int i = 0; i < n; i++) {
printf("%d ", &data[i]);
}
}
Try this:
#include <stdio.h>
int main() {
int data[100];
int i;
int counter = 0;
for (i = 0; i < 100; i++) {
printf("Input your number:\n");
scanf("%d", &data[i]);
counter++;
if (data[i] <= 0) {
break;
}
}
printf("Your array:");
for (int j = 0; j < counter - 1; j++) {
printf("%d ", data[j]);
}
}
The problem was that you had printf("%d ", &data[i]); instead of printf("%d ", data[i]);.
And also you've trying to get the sizeof() of an element data[i], not the size of the whole array. That's why there's counter in my code.
int n = sizeof(data[i]);
this is wrong, you want
int n = i;
sizeof(data[i]) gives you the size of an int (4 on my machine)
On the other hand, you need to check the result of scanf, if a bad input is entered do not increment the counter, something like:
int i = 0;
while (i < 100)
{
int res = scanf("%d", &data[i]);
if (res == EOF)
{
break;
}
if (res == 1)
{
if (data[i] <= 0)
{
break;
}
i++;
}
else
{
// Sanitize stdin
int c;
while ((c = getchar()) != '\n');
}
}
Finally, scanf wants a pointer to the object, but this is not the case of printf:
printf("%d ", &data[i])
should be
printf("%d ", data[i])

Bug Histogram Display in C

i want to do a histogram vertical display of my "election".
My code work just it seems to display wrongly the vote for the 10,11,12,13 value because i think there is 2 numbers ...
thank you for your time ;)
int main() {
char character ;
int TAB[12] = {0} ;
int vote = 0;
int I;
printf("Please enter a character:\n"); //character for the display
scanf(" %c", &character); // character we want to display in the histogram
printf("Please enter votes\n");
while(1) {
scanf("%d", &vote);
if (vote == -1) {
break;
}
TAB[vote-1]++; //save the vote into the array
}
printf("Histogram :\n");
/* Search for the maximum value */
int MAX=0;
for (I=0; I<12; I++)
{
if(TAB[I]>TAB[MAX]) MAX=I;
}
int maximum = TAB[MAX]; // maximum value
while (maximum > 0) {
for (I = 0; I < 12; I++) {
if (TAB[I] == maximum) {
printf("%c ",character);
TAB[I] = (TAB[I] - 1) ;
}
else {
printf(" ");
}
}
maximum= maximum - 1;
printf("\n");
}
for (I = 0; I < 13; I++) {
printf("%d ",I+1); // display the number of each candidat
}
printf("\n"); // go to the line
return 0;
}
You shouldn't use magic number 12, use like #define VOTE_MAX 13
For the range of vote, use if (vote <= 0 || vote > VOTE_MAX)
Format output, like printf("%2c ", character);
The line for (I = 0; I < 13; I++) { should be for (I = 0; I < 12; I++) {
The following code could work:
#include <stdio.h>
#define VOTE_MAX 13
int main() {
char character;
int TAB[VOTE_MAX] = {0};
int vote = 0;
printf("Please enter a character:\n"); // character for the display
scanf(" %c", &character); // character we want to display in the histogram
printf("Please enter votes\n");
while (1) {
scanf("%d", &vote);
if (vote <= 0 || vote > VOTE_MAX) {
break;
}
TAB[vote - 1]++; // save the vote into the array
}
printf("Histogram :\n");
/* Search for the maximum value */
int MAX = 0;
for (int i = 0; i < VOTE_MAX; ++i) {
if (TAB[i] > TAB[MAX]) MAX = i;
}
int maximum = TAB[MAX]; // maximum value
while (maximum > 0) {
for (int i = 0; i < VOTE_MAX; ++i) {
if (TAB[i] == maximum) {
printf("%2c ", character);
--TAB[i];
} else {
printf("%2c ", ' ');
}
}
--maximum;
printf("\n");
}
for (int i = 0; i < VOTE_MAX; ++i) {
printf("%2d ", i + 1); // display the number of each candidat
}
printf("\n"); // go to the line
return 0;
}
You need to add an extra space for the cases where I is 10 or higher.
Like:
for (I = 0; I < 12; I++) {
if (TAB[I] == maximum) {
printf("%c ",character);
TAB[I] = (TAB[I] - 1) ;
}
else {
printf(" ");
}
if (I >= 9) printf(" "); // Add extra space for 10, 11 and 12
}
BTW: your input method should be improved. Currently the user can enter values that will make your write outside the array. At least do something like:
while(1) {
if (scanf("%d", &vote) != 1) break; // Catch illegal input
if (vote <= 0 || vote >= 13) { // Only allow vote to be 1, 2, …, 10, 11, 12
break;
}
TAB[vote-1]++; //save the vote into the array
}

Why does it say 'expected declaration specifiers before 'main''

first of all, I understand mostly everything in this program that I copied from this book.
second, i just wanted to see if it worked ,
the only problem is that it says 'expected declaration specifiers before 'main''
and i don't know what it means
ps this is a really long program (300+ lines)
#include <stdio.h>
#include <time.h>
#include <ctype.h>
#include <stdlib.h>
#define FALSE 0
#define TRUE 1
void printGreeting();
int getBet();
char getSuit(int suit);
char getRank(int rank);
void getFirstHand(int cardRank[], int cardSuit[]);
void getFinalHand
(int cardRank[], int cardSuit[], int finalRank[], int finalSuit[], int
ranksinHand[], int suitsinHand[])
int analyzeHand(int ranksinHand[], int suitsinHand[]);
main()
{
int bet;
int bank = 100;
int i;
int cardRank [5];
int cardSuit [5];
int finalRank[5];
int finalSuit[5];
int ranksinhand[13];
int suitsinhand[4];
int winnings;
time_t t;
char suit, rank, stillPlay;
printGreeting();
do{
bet = getBet();
srand(time(&t));
getFirstHand(cardRank, cardSuit);
printf("Your five cards: \n\n");
for (i = 0; i < 5; i++)
{
suit = getSuit(cardsSuit[i]);
rank = getRank(cardRank[i]);
printf("Card #%d: %c%c\n\n", i+1, rank, suit);
}
for (i=0; i < 4; i++)
{
suitsinHand[i] = 0;
}
for (i=0; i < 13; i++)
{
ranksinHand[i] = 0;
}
getFinalHand(cardRank, cardSuit, finalRank, finalSuit, ranksinHand,
suitsinHand);
printf("Your five final cards:\n\n");
for (i = 0; i < 5; i++)
{
suit = getSuit(finalSuit[i]);
rank = getRank(finalRank[i]);
printf("Card #%d: %c%c\n\n", i+1, rank, suit);
}
winnings = analyzeHand(ranksinHand, suitsinHand);
printf("You won %d!\n\n", bet*winnings);
bank = bank - bet + (bet*winnings)
printf("\n\nYour bank is now %d.\n\n", bank);
printf("Want to play again? ");
scanf(" %c", &stillPlay);
}while (toupper(stillPlay) == 'Y');
return;
}
/*************************************************************************/
void printGreeting();
{
printf("**********************************************************\n\n");
printf("\n\n\tWelcome to the Absolute Beginner's Casino\n\n");
printf("\tHome of the Video Draw Poker");
printf("**********************************************************\n\n");
printf("Here are the rules\n");
printf("You start with 100 credits, and you make a bet from");
printf("1 to 5 credits.\n");
printf("You are dealt 5 cards, and then you choose which ");
printf("cards to keep");
printf("or discard\n");
printf("You want to make the best possible hand.\n");
printf("\nHere is the table for winnings (assuming a ");
printf("bet of 1 credit):");
printf("\nPair \t\t\t\t1 credit");
printf("\nTwo pairs\t\t\t2 credits");
printf("\nThree of a kind\t\t\t3 credits");
printf("\nStraight \t\t\t4 credits");
printf("Flush\t\t\t\t5 credits");
printf("Full House\t\t\t8 credits");
printf("Four of a Kind\t\t\t10 credits");
printf("Straight Flush\t\t\t20 credits");
printf("\n\nHave fun!!\n\n");
}
void getFirstHand(int cardRank[], int cardSuit[]);
{
int i,j;
int carDup;
for(i=0; i < 5; i++)
{
carDup = 0;
do{
cardRank[i] = (rand() % 13);
cardSuit[i] = (rand() % 4);
for (j=0; j < i; j++)
{
if ((cardRank[i] == cardRank[j] &&
cardSuit[i] == cardSuit[j]))
{
carDup = 1;
}
}
}while (carDup == 1;);
}
}
char getSuit(int suit)
{
switch
{
case 0:
return('C');
case 1:
return('D');
case 2:
return('H');
case 3:
return('S');
}
}
char getRank(int rank)
{
switch (rank)
{
case 0:
return('A');
case 1:
return('2');
case 2:
return('3');
case 3:
return('4');
case 4:
return('5');
case 5:
return('6');
case 6:
return('7');
case 7;
return('8');
case 8:
return('9');
case 9:
return('T');
case 10:
return('J');
case 11:
return('Q');
case 12:
return('K');
}
}
int getBet()
{
int bet;
do
{
printf("How much do you want to bet?(Enter a number");
printf("from 1 to 5, or 0 to quit the game): ");
scanf(" %d", &bet);
if (bet >= 1 && bet <= 5)
{
return(bet);
}
else if (bet == 0)
{
exit(1);
}
else
{
printf("\n\nPlease enter a bet from 1-5 or ");
printf("0 to quit the game\n\n");
}
}while ((bet < 0) || (bet > 5));
}
int analyzeHand(int ranksinHand[], int suitsinHand[])
{
int num_consec = 0;
int i, rank, suit;
int straight = FALSE;
int flush = FALSE;
int four = FALSE;
int three = FALSE;
int pairs = 0;
for (suit = 0; suit < 4; suit++)
if (suitsinHand[suit] == 5)
flush = TRUE;
rank = 0;
while (ranksinHand[rank] == 0)
rank++;
for (; rank < 13 && ranksinHand[rank]; rank++)
num_consec++;
if(num_consec == 5) {
straight = TRUE;
}
for (rank = 0; rank < 13; rank++){
if (ranksinHand[rank] == 4)
four == TRUE;
if (ranksinHand[rank] == 3)
three == TRUE;
if (ranksinHand[rank] == 2)
pairs++;
}
if (straight && flush){
printf("Straight Flush\n\n");
return(20);
}
else if (four){
printf("Four of a kind\n\n");
return (10);
}
else if (three && pairs == 1){
printf("Full House\n\n");
return (8);
}
else if (flush){
printf("Flush\n\n");
return (5);
}
else if (straight){
printf("Straight\n\n");
return (4);
}
else if (three){
printf("Three of a Kind\n\n");
return (3);
}
else if (pairs == 2){
printf("Two Pairs\n\n");
return (2);
}
else if (pairs == 1){
printf("Pair\n\n");
return (1);
}
else{
printf("High Card\n\n");
return (0);
}
}
void getFinalHand
(int cardRank[], int cardSuit[], int finalRank[], int finalSuit[], int
ranksinHand[], int suitsinHand[])
{
int i, j, carDup;
char suit, rank, ans;
for (i=0; i < 5; i++)
{
suit = getSuit(cardSuit[i]);
rank = getRank(cardRank[i]);
printf("Do you want to keep card #%d: %c%c", i+1, rank, suit);
printf("\nPlease answer (Y/N):");
scanf(" %c", &ans);
if (toupper(ans) == 'Y')
{
finalRank[i] = cardRank[i];
finalSuit[i] = cardSuit[i];
ranksinHand[finalRank[i]]++;
suitsinHand[finalSuit[i]]++;
continue;
}
else if (toupper(ans) == 'N')
{
carDup = 0;
do{
carDup = 0;
finalRank[i] = (rand() % 13);
finalSuit[i] = (rand() % 4);
for (j=0; j < 5; j++)
{
if((finalRank[i] == finalRank[j]) && (finalSuit[i] ==
finalSuit[j]))
{
carDup = 1;
}
}
for (j=0; j < i; j++)
{
if((finalRank[i] == finalRank[j]) && (finalSuit[i] ==
finalSuit[j]))
{
carDup = 1;
}
}
}while (carDup == 1);
ranksinHand[finalRank[i]]++;
suitsinHand[finalSuit[i]]++;
}
}
}
By convention main() must return an integer. You have to declare it like that:
int main()
{
// Your method
return 0;
}
int mainor
void main
would do the work. Here, int main is shown to be the C standard. Refer to
Return type of main() too.

RSA Encryption C code

I am having trouble doing my homework.
I am doing an RSA application which can encrypt and decrypt.
The problem is that after I Input things to encrypt the results are weird and I can't decrypt anything. This is because when I copied the results of encryption which are symbols, I got more weird stuffs.
I'm guessing it has something to do with my formula getting negative ASCIIs as results.
Below is what I tried, and, in order to understand what I meant by weird, just compile and try it out(I have some unused stuffs which I haven't removed yet):
Output:
Code:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <math.h>
#define boolean int
#define true 1
#define false 0
//===================================================//
int p = 0;
int q = 0;
int n = 0;
int m = 0;
int divider = 2;
int tempdivider = 2;
int initial = 0;
int x = 0;
int y = 0;
char msg[100];
char alphabet[27];
//===================================================//
void cls();
void menu();
void init();
void reinit();
void inputencrypt();
//int encrypt(int num);
void encrypt();
char decrypt(char text[]);
int fpb(int num);
int d(int num);
int primecheck(int a);
boolean checkdigit(char text[]);
//===================================================//
int main() {
frontpage();
init();
menu();
getchar();
return 0;
}
//===================================================//
void cls() {
for (int i = 0;i < 25;i++) {
printf("\n");
}
}
//===================================================//
boolean checkdigit(char text[]) {
int len = strlen(text);
for (int i = 0;i < len;++i) {
if (text[i]<'0' || text[i]>'9') {
return false;
}
}
return true;
}
int primecheck(int a) {
if (a == 1) {
return false;
}
for (int i = 2;i < a;i++) {
if (a%i == 0) {
return false;
}
}
return true;
}
//===================================================//
void reinit() {
for (int i = 1;i < 27;i++) {
alphabet[i] = 'a' + i - 1;
}
p = 0;
q = 0;
n = 0;
m = 0;
divider = 2;
tempdivider = 2;
initial = 120;
x = 0;
y = 0;
}
void init() {
reinit();
do {
printf("p = ");
scanf("%d", &p);fflush(stdin);
if (!primecheck(p)) {
printf("must be prime number! \n");
}
} while (!primecheck(p));
do {
printf("q = ");
scanf("%d", &q);fflush(stdin);
if (!primecheck(q)) {
printf("must be prime number! \n");
}
} while (!primecheck(q));
n = p*q;
m = (p - 1)*(q - 1);
initial = m;
x = fpb(m);
y = d(m);
printf("n = %d\n", n);
printf("m = %d\n", m);
printf("e = %d\n", x);
printf("d = %d\n", y);
system("pause");
}
//===================================================//
void menu() {
char input[2];
int input1 = 0;
do {
do {
cls();
printf("main menu\n");
printf("================\n");
printf("1. encrypt\n");
printf("2. decrypt\n");
printf("3. exit\n");
printf(">> ");
scanf("%s", input);fflush(stdin);
if (checkdigit(input)) {
input1 = atoi(input);
}
} while (!checkdigit(input));
switch (input1) {
case 1:
int c;
char encrypted[100];
char word[100];
printf("input word to encrypt : ");
scanf(" %[^\n]", word);fflush(stdin);
for (int i = 0;i < strlen(word);i++) {
if (word[i] == ' ') {
encrypted[i] = ' ';
//i++;
}
else {
for (int j = 1;j < 27;j++) {
if (word[i] == alphabet[j]) {
c = 0;
c = pow(j, x);
c = c%n;
encrypted[i] = c;
break;
}
}
}
}
printf("\n\nWord ASCII [ ");
for (int i = 0;i < strlen(word);i++) {
//printf("%d", c);
printf("%d ", word[i]);
}
printf(" ]\n");
printf("\n\nEncrypted ASCII [ ");
for (int i = 0;i < strlen(word);i++) {
//printf("%d", c);
printf("%d ", encrypted[i]);
}
printf(" ]\n");
printf("\n\nEncrypted [ ");
for (int i = 0;i < strlen(word);i++) {
//printf("%d", c);
printf("%c", encrypted[i]);
}
printf(" ]");
printf("\n\n\n");
system("pause");
break;
case 2:
int temp[100];
char decrypted[100];
char wordx[100];
int h;
printf("input word to decrypt : ");
scanf(" %[^\n]", wordx);fflush(stdin);
for (int i = 0;i < strlen(wordx);i++) {
temp[i] = wordx[i];
//temp[i] -= 97;
//printf("%d ::: %c\n", temp[i], temp[i]);
}
for (int i = 0;i < strlen(wordx);i++) {
if (wordx[i] == ' ') {
decrypted[i] = ' ';
}
else {
h = 0;
h = pow(temp[i], y);
h = h%n;
decrypted[i] = h;
for (int j = 1;j < 27;j++) {
if (decrypted[i] == j) {
decrypted[i] = alphabet[j];
}
}
}
}
printf("\n\nWord ASCII [ ");
for (int i = 0;i < strlen(wordx);i++) {
//printf("%d", c);
printf("%d ", wordx[i]);
}
printf(" ]\n");
printf("\n\nDecrypted ASCII [ ");
for (int i = 0;i < strlen(wordx);i++) {
//printf("%d", c);
printf("%d ", decrypted[i]);
}
printf(" ]\n");
printf("\n\nDecrypted [ ");
for (int i = 0;i < strlen(wordx);i++) {
//printf("%d", decrypted[i]);
printf("%c", decrypted[i]);
}
printf(" ]");
printf("\n\n\n");
system("pause");
break;
}
} while (input1 != 3);
}
//===================================================//
int fpb(int num) {
if (!primecheck(num)) {
if (num%divider == 0) {
num = num / divider;
divider = 2;
}
else {
divider++;
}
fpb(num);
}
else if (primecheck(num)) {
if (!primecheck(num + divider)) {
tempdivider++;
divider = tempdivider;
num = initial;
fpb(num);
}
else {
return num + divider;
}
}
}
int d(int num) {
for (int i = 1;i < num;i++) {
if ((x*i) % num == 1) {
return i;
}
}
}
You have a general comprehension problem. Your console is only able to represent 96 characters correctly (known as printable 7bit-ASCII characters, 0x20 to 0x7F), but a byte can hold 255 different values. Your encryption algorithm does not care about this limited range, it will encrypt any value in the range [0..255] into another value in the range [0..255]. So your ASCII input characters will most likely be encrypted into values that cannot be represented by your console correctly. Copy&Past will not work correctly for non-printable characters (like 0x0B, which is a tab).
But now you will wonder: Why does that work for e.g. E-Mails? Simply: Because those characters are converted into an ASCII representation. Please google a bit for Base64 encoding.
As an alternative, you can always stream your encrypted characters into a file and later read back from that. This way you will bypass the limitations of your console.
Btw: Please have a look at the documentation of printf() and you will know, why you get those negative values.
The encrypt option has these three statements consecutively
c = 0;
c = pow(j, x);
c = c%n;
and the last of those will leave c in the range 0..(n-1).
Apart from that, there is no else clause and int c; can remain uninitialised.
So all in all it is inevitable that when you print c values as characters you will get "weird" results.
As for negative values, char encrypted[100]; is probably signed char so any integer value in the range 128..255 assigned to that, although undefined behaviour, may possibly show up as a negative number because the signed char is promoted back to int when passed as format %d to printf.

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