Create hello.c

Tanmay/pset1/credit.c

@@ -0,0 +1,34 @@
+#include<stdio.h>
+int main()
+{
+
+    long long int num;
+    int oddsum=0,evensum=0,finalsum=0;
+    printf("Enter your card number: ");
+    scanf("%lld",&num);
+    for(long long int a=num;a>0;a=a/100)
+    {
+            oddsum=oddsum+(a%10);
+    }
+    for(long long int b=num/10;b>0;b/=100)
+    {
+            evensum+=((2*(b%10))/10)+((2*(b%10))%10);
+    }
+    finalsum=oddsum+evensum;
+    if(finalsum%10!=0)
+        printf("Invalid card");
+    else
+    {
+        if(num/1000000000000000==0)
+            printf("It's an AMEX");
+        else if(num/10000000000000==0)
+            printf("It's a VISA");
+        else if(num/1000000000000000==4)
+            printf("It's a VISA");
+            else
+                printf("It's a MASTERCARD");
+    }
+ }
+
+
+

Tanmay/pset2/caeser.c

@@ -0,0 +1,8 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main()
+{
+    printf("Hello world!\n");
+    return 0;
+}

Tanmay/pset2/vigenere.c

@@ -0,0 +1,70 @@
+#include <stdio.h>
+#include <cs50.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+
+
+
+int main(int argc, string argv[])
+{
+
+    if(argc != 2)
+    {
+        printf("Desired format: ./caesar k");
+        return 1;
+    }
+
+    string k = argv[1];
+
+    //Checks if the key is only alphabetical
+    for(int i = 0, n = strlen(k); i < n; i++)
+    {
+        if(!isalpha(k[i]))
+        {
+            printf("Key must contain only alphabets");
+            return 1;
+        }
+    }
+
+    string k_upper = k;
+
+
+    //Converts the whole key into uppercase
+    for(int i = 0, n = strlen(k_upper); i < n; i++)
+    {
+        k_upper[i] = toupper(k_upper[i]);
+    }
+
+    int letter = 0;
+    int key_length = strlen(k_upper);
+
+    string input = GetString();
+
+    for(int i = 0, n = strlen(input); i < n; i++)
+    {
+        int shift = k_upper[letter % key_length] - 65; //Number of shifts needed for te current letter in plaintext
+
+        if(isupper(input[i]))
+        {
+            if(input[i] + (shift % 26) > 'Z')
+            {
+                input[i] -= 26;
+            }
+            input[i] += shift % 26;
+            letter++;
+        }
+        else if(islower(input[i]))
+        {
+            if(input[i] + (shift % 26) > 'z')
+            {
+                input[i] -= 26;
+            }
+            input[i] += shift % 26;
+            letter++;
+        }
+
+    }
+
+    printf("%s\n", input);
+}

Tanmay/pset3/helpers.c

@@ -0,0 +1,56 @@
+#include <cs50.h>
+#include <stdio.h>
+#include <string.h>
+#include <math.h>
+
+#include "helpers.h"
+
+int duration(string fraction)
+{
+    int num, den;
+    num = fraction[0] - '0';
+    den = fraction[2] - '0';
+    int result = 1;
+    result *= num;
+    result *= (8 / den);
+    return result;
+}
+
+//Calculates frequency (in Hz) of a note
+int frequency(string notei)
+{
+    double frequency;
+    int num;
+    string temp;
+    char note[3];
+    for(int i = 0; i < strlen(notei); i++)
+    {
+        //printf("%d",i);
+        if(!((notei[i] >= '0') && (notei[i] <= '9'))) note[i] = notei[i];
+        else
+        {
+            num = notei[i] - '0';
+        }
+    }
+    string values[12][2] = {{"C ", "  "}, {"C#", "Db"}, {"D ", "  "}, {"D#", "Eb"}, {"E ", "  "}, {"F ", "  "}, {"F#", "Gb"}, {"G ", "  "}, {"G#", "Ab"}, {"A ", "  "}, {"A#", "Bb"}, {"B ", "  "}};
+    if(strlen(note) == 1) temp = strcat(note, " ");
+    else temp = note;
+    for(int i = 0; i < 12; i++)
+    {
+        for(int j = 0; j < 2; j++)
+        {
+            if(!(strcmp(temp, values[i][j])))
+            {
+                frequency = pow(2.0, ((((float) i) - 9) / 12.0));
+            }
+        }
+    }
+    frequency *= (440.0 * pow(2.0, ((float) num) - 4.0));
+    return (int) round(frequency);
+}
+
+bool is_rest(string s)
+{
+    if(strcmp(s,"")) return false;
+    return true;
+}

Tanmay/pset4/recover.c

@@ -0,0 +1,56 @@
+#include <stdio.h>
+#include <cs50.h>
+#include <stdint.h>
+
+#define BLOCK_SIZE 512
+
+typedef uint8_t BYTE;
+
+int main(int argc, char *argv[])
+{
+
+    if (argc != 2)
+    {
+        fprintf(stderr, "Usage: recover infile\n");
+        return 1;
+    }
+
+    char *infile = argv[1];
+    FILE *inptr = fopen(infile, "r");
+
+    if (inptr == NULL)
+    {
+        fprintf(stderr, "Could not open %s.\n", infile);
+        return 2;
+    }
+
+    BYTE buffer[512];
+    int imageCount = 0;
+    char filename[8];
+    FILE *outptr = NULL;
+
+     while (!feof(inptr))
+    {
+        int bytesRead = fread(buffer, sizeof(BYTE), BLOCK_SIZE, inptr);
+
+        bool containsJpegHeader = buffer[0] == 0xff && buffer[1] == 0xd8 && buffer[2] == 0xff && (buffer[3] & 0xf0) == 0xe0;
+
+        if (containsJpegHeader)
+        {
+           if(outptr!=NULL)
+           {
+            fclose(outptr);
+            imageCount++;
+            }
+            sprintf(filename, "%03i.jpg", imageCount);
+            outptr = fopen(filename, "w");
+        }
+
+        if (outptr != NULL)
+        {
+            fwrite(buffer, sizeof(BYTE), bytesRead, outptr);
+        }
+    }
+    fclose(outptr);
+    fclose(inptr);
+}

Tanmay/pset4/resize/bmp.h

@@ -0,0 +1,77 @@
+/**
+ * BMP-related data types based on Microsoft's own.
+ */
+
+#include <stdint.h>
+
+/**
+ * Common Data Types
+ *
+ * The data types in this section are essentially aliases for C/C++
+ * primitive data types.
+ *
+ * Adapted from https://msdn.microsoft.com/en-us/library/cc230309.aspx.
+ * See http://en.wikipedia.org/wiki/Stdint.h for more on stdint.h.
+ */
+typedef uint8_t  BYTE;
+typedef uint32_t DWORD;
+typedef int32_t  LONG;
+typedef uint16_t WORD;
+
+/**
+ * BITMAPFILEHEADER
+ *
+ * The BITMAPFILEHEADER structure contains information about the type, size,
+ * and layout of a file that contains a DIB [device-independent bitmap].
+ *
+ * Adapted from https://msdn.microsoft.com/en-us/library/dd183374(v=vs.85).aspx.
+ */
+typedef struct
+{
+    WORD bfType;
+    DWORD bfSize;
+    WORD bfReserved1;
+    WORD bfReserved2;
+    DWORD bfOffBits;
+} __attribute__((__packed__))
+BITMAPFILEHEADER;
+
+/**
+ * BITMAPINFOHEADER
+ *
+ * The BITMAPINFOHEADER structure contains information about the
+ * dimensions and color format of a DIB [device-independent bitmap].
+ *
+ * Adapted from https://msdn.microsoft.com/en-us/library/dd183376(v=vs.85).aspx.
+ */
+typedef struct
+{
+    DWORD biSize;
+    LONG biWidth;
+    LONG biHeight;
+    WORD biPlanes;
+    WORD biBitCount;
+    DWORD biCompression;
+    DWORD biSizeImage;
+    LONG biXPelsPerMeter;
+    LONG biYPelsPerMeter;
+    DWORD biClrUsed;
+    DWORD biClrImportant;
+} __attribute__((__packed__))
+BITMAPINFOHEADER;
+
+/**
+ * RGBTRIPLE
+ *
+ * This structure describes a color consisting of relative intensities of
+ * red, green, and blue.
+ *
+ * Adapted from https://msdn.microsoft.com/en-us/library/dd162939(v=vs.85).aspx.
+ */
+typedef struct
+{
+    BYTE rgbtBlue;
+    BYTE rgbtGreen;
+    BYTE rgbtRed;
+} __attribute__((__packed__))
+RGBTRIPLE;