Bit Stuffing :

Source Code:

File Name: bit_stuffing.c

#include<stdio.h>

void main() {
    int ip_frame[100], op_frame[200];
    int i, j = 0, n;
    int count = 0;

    printf("Enter frame length: ");
    scanf("%d", &n);

    printf("Enter input frame (0's and 1's only):\n");
    for(i = 0; i < n; i++) {
        scanf("%d", &ip_frame[i]);
    }

    // Bit stuffing logic
    for(i = 0; i < n; i++) {
        op_frame[j++] = ip_frame[i];

        if(ip_frame[i] == 1) {
            count++;
            if(count == 5) {
                op_frame[j++] = 0;  // Stuff a 0 after five 1s
                count = 0;          // Reset count after stuffing
            }
        } else {
            count = 0;  // Reset count if a 0 is found
        }
    }

    printf("\nAfter bit stuffing, the frame is:\n");
    for(i = 0; i < j; i++) {
        printf("%d", op_frame[i]);
    }
    printf("\n");
}

Output:

$ gcc bit_stuffing.c
$ ./a.out
enter frame length: 9
Enter input frame (0's & 1's only) :
0
1
0
1
1
1
1
1
1

After stuffing, the frame is:
0101111101

Character Stuffing :

Source Code:

File Name: char_stuffing.c

#include<stdio.h>
#include<string.h>

void main()
{
    int i = 0, j = 0, n, pos;
    char a[20], b[100], ch;

    printf("Enter the string:\n");
    scanf("%s", a);

    n = strlen(a);

    printf("Enter position to insert the character:\n");
    scanf("%d", &pos);

    // Validate position
    while(pos < 1 || pos > n + 1)
    {
        printf("Invalid position, enter again: ");
        scanf("%d", &pos);
    }

    getchar(); // Clear newline left by previous scanf
    printf("Enter the character to stuff:\n");
    ch = getchar();

    // Add starting frame delimiter
    b[0] = 'd'; b[1] = 'l'; b[2] = 'e'; b[3] = 's'; b[4] = 't'; b[5] = 'x';
    j = 6;

    for (i = 0; i < n; i++)
    {
        // Insert stuffing character at given position
        if (i == pos - 1)
        {
            b[j++] = 'd'; b[j++] = 'l'; b[j++] = 'e';
            b[j++] = ch;
            b[j++] = 'd'; b[j++] = 'l'; b[j++] = 'e';
        }

        // Escape 'dle' sequence
        if (a[i] == 'd' && a[i + 1] == 'l' && a[i + 2] == 'e')
        {
            b[j++] = 'd'; b[j++] = 'l'; b[j++] = 'e';
        }

        b[j++] = a[i];
    }

    // If position is at the end
    if (pos == n + 1)
    {
        b[j++] = 'd'; b[j++] = 'l'; b[j++] = 'e';
        b[j++] = ch;
        b[j++] = 'd'; b[j++] = 'l'; b[j++] = 'e';
    }

    // Add ending frame delimiter
    b[j++] = 'd'; b[j++] = 'l'; b[j++] = 'e'; b[j++] = 'e'; b[j++] = 't'; b[j++] = 'x';
    b[j] = '\0';

    printf("\nFrame after stuffing:\n%s\n", b);
}

Output:

$ gcc char_stuffing.c
$ ./a.out
Enter the string:
madhu
Enter position to insert the character:
2
Enter the character to stuff:
k

Frame after stuffing:
dlestxmdlekdleadhudleetx

Character Count :

Source Code:

File Name: char_count.c

#include<stdio.h>
#include<string.h>

char data[20][20];
int n;

int main() {
    int i, j, ch;
    char tmp[20][30];  // Stores frames with character count

    printf("Enter the number of frames: ");
    scanf("%d", &n);
    getchar();  // clear newline after scanf

    // Input the frames
    for (i = 1; i <= n; i++) {
        printf("Frame %d: ", i);
        fgets(data[i], sizeof(data[i]), stdin);
        data[i][strcspn(data[i], "\n")] = '\0';  // remove newline
    }

    // Creating frames with count prefix
    for (i = 1; i <= n; i++) {
        int len = strlen(data[i]);
        tmp[i][0] = len + '0';  // store count as char (e.g., '5')
        tmp[i][1] = '\0';
        strcat(tmp[i], data[i]);  // append actual data after count
    }

    // AT THE SENDER
    printf("\n\t\tAT THE SENDER:\n");
    printf("Data as frames:\n");
    for (i = 1; i <= n; i++) {
        printf("Frame %d: ", i);
        puts(tmp[i]);
    }

    printf("Data transmitted: ");
    for (i = 1; i <= n; i++) {
        printf("%s", tmp[i]);
    }

    // AT THE RECEIVER
    printf("\n\n\t\tAT THE RECEIVER:\n");
    printf("The data received: ");

    for (i = 1; i <= n; i++) {
        ch = tmp[i][0] - '0';  // get count
        for (j = 0; j < ch; j++) {
            data[i][j] = tmp[i][j + 1];  // skip count character
        }
        data[i][j] = '\0';  // null terminate
    }

    printf("\nData after removing count characters: ");
    for (i = 1; i <= n; i++) {
        printf("%s", data[i]);
    }

    printf("\n\nData in frame form:\n");
    for (i = 1; i <= n; i++) {
        printf("Frame %d: ", i);
        puts(data[i]);
    }

    return 0;
}

Output:

$ gcc char_count.c
$ ./a.out
Enter the number of frames: 3
Frame 1: Computer
Frame 2: Networks
Frame 3: Lab

                AT THE SENDER:
Data as frames:
Frame 1: 8Computer
Frame 2: 8Networks
Frame 3: 3Lab
Data transmitted: 8Computer8Networks3Lab

                AT THE RECEIVER:
The data received:
Data after removing count characters: ComputerNetworksLab

Data in frame form:
Frame 1: Computer
Frame 2: Networks
Frame 3: Lab