Added all the assignments

README.md

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+# BTech Assignments
+A repository of my BTech assignments for papers:
+* IT351:      Data Structures (C)
+* IT451:      Computer Organisation and Architecture (VHDL)
+* IT453:      Computer Graphics (C)
+* IT455:      Modelling and Simulation (MATLAB)
+* IT552:      Operating System (C)
+* IT553:      Database Management System (SQL)
+* IT651:      Design & Analysis of Algorithms (C)
+* IT652:      Compiler Design (C)

compiler-design/assg-1/README.md

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+# Assignment 1
+
+## Questions
+
+1. Write a C program to traverse a set of input strings through an FS for integer & floating point number; output is whether the strings are integers or floating point.
+
+2. Write a C program to filter comments: ```//``` & ```/**/``` from a given input file.
+
+3. Implement double buffering technique for Lexical Analyzer to separate numbers (int & float), tokens, and remove white spaces and comments. Report lexical errors if there exists any. Assume N = 128, input a C program from file, output numbers, tokens, errors (if any).

compiler-design/assg-1/input-1.txt

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+123
+14a
+4.501
+174.5.3
+01.67
+88.a
+.51
+87..
+12.
+077
+0

compiler-design/assg-1/input-2.txt

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+#include <stdio.h>
+
+int main(int argc, char *argv[]) {
+    // this is an inline comment
+
+    // this is another inline comment
+
+    int a = 5; // define an integer
+
+    /* this is
+    a multiline
+    comment spread over
+    4 lines */
+
+    a = a + 9 * 5;
+    printf("a /*is equal to*/= %d\n", a);
+
+
+    return 0;
+}

compiler-design/assg-1/input-3.txt

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+int main(int argc, char *argv[]) {
+    // this is an inline comment
+
+    // this is another inline comment
+
+    int a = 5; // define an integer
+
+    /* this is
+    a multiline
+    comment spread over
+    4 lines */
+
+    int b = 9;
+    b++;
+
+    a = b +  9 * a;
+
+    printf("a /*is equal to*/= %d\n", a);
+
+    int c = b * 1d;   float n = 0.05;
+    n = (float) a / n;
+
+    c <<= 2;
+
+
+    return 0;
+}

compiler-design/assg-1/output-1.txt

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+Integer
+Invalid
+Float
+Invalid
+Invalid
+Invalid
+Float
+Invalid
+Invalid
+Invalid
+Integer

compiler-design/assg-1/output-2.txt

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+ this is an inline comment
+
+ this is another inline comment
+
+ define an integer
+
+ this is
+    a multiline
+    comment spread over
+    4 lines 
+

compiler-design/assg-1/output-3.txt

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+KEYWORD		int
+IDENTIFIER	main
+SEPARATOR	(
+KEYWORD		int
+IDENTIFIER	argc
+SEPARATOR	,
+KEYWORD		char
+OPERATOR	*
+IDENTIFIER	argv
+SEPARATOR	[
+SEPARATOR	]
+SEPARATOR	)
+SEPARATOR	{
+KEYWORD		int
+IDENTIFIER	a
+OPERATOR	=
+INTEGER		5
+SEPARATOR	;
+KEYWORD		int
+IDENTIFIER	b
+OPERATOR	=
+INTEGER		9
+SEPARATOR	;
+IDENTIFIER	b
+OPERATOR	++
+SEPARATOR	;
+IDENTIFIER	a
+OPERATOR	=
+IDENTIFIER	b
+OPERATOR	+
+INTEGER		9
+OPERATOR	*
+IDENTIFIER	a
+SEPARATOR	;
+IDENTIFIER	printf
+SEPARATOR	(
+STRING		"a /*is equal to*/= %d\n"
+SEPARATOR	,
+IDENTIFIER	a
+SEPARATOR	)
+SEPARATOR	;
+KEYWORD		int
+IDENTIFIER	c
+OPERATOR	=
+IDENTIFIER	b
+OPERATOR	*
+INVALID		1d
+SEPARATOR	;
+KEYWORD		float
+IDENTIFIER	n
+OPERATOR	=
+FLOAT		0.05
+SEPARATOR	;
+IDENTIFIER	n
+OPERATOR	=
+SEPARATOR	(
+KEYWORD		float
+SEPARATOR	)
+IDENTIFIER	a
+OPERATOR	/
+IDENTIFIER	n
+SEPARATOR	;
+IDENTIFIER	c
+OPERATOR	<<=
+INTEGER		2
+SEPARATOR	;
+KEYWORD		return
+INVALID		0
+SEPARATOR	;
+SEPARATOR	}

compiler-design/assg-1/q1.c

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+/*
+Valid Integers:
+  begins with 1 - 9, followed by any number
+    of digits between 0 - 9
+Valid Floating Point numbers:
+  begins with 0., followed by any number of
+    digits between 0 - 9
+  begins with ., followed by any number of
+    digits between 0 - 9
+  begins with 1 - 9, followed by any number
+    of digits between 0 - 9, followed by .,
+    followed any whole number of digits
+    between 0 - 9
+*/
+
+
+#include <stdio.h>
+#include <string.h>
+
+
+int getType(int, char *);
+
+
+int main(int argc, char *argv[]) {
+    FILE *fi = fopen("input-1.txt", "r");   // input file
+    FILE *fo = fopen("output-1.txt", "w");  // output file
+    if (fi == NULL) 
+        goto exit;                  // exit if no input file
+
+    // run until input strings exist
+    while (!feof(fi)) {
+        char string[64];
+        fscanf(fi, "%s", string);
+
+        int flag = getType(strlen(string), string);
+        if (flag == 1)
+            fprintf(fo, "Integer\n");
+        else if (flag == 2)
+            fprintf(fo, "Float\n");
+        else
+            fprintf(fo, "Invalid\n");
+    }
+
+    fclose(fi);
+    fclose(fo);
+    exit: return 0;
+}
+
+
+// function to determine whether passed string is
+// an Integer, Float, or Invalid
+int getType(int len, char *s) {
+    int state = 0, p = 0;
+
+    /*
+    state 0: initial state
+    state 1: first digit is between 1 - 9
+             (end state)
+    state 2: decimal has been encountered
+    state 3: there is atleast one digit after decimal
+             (end state)
+    state 4: first digit is 0
+    state 5: string isn't an integer or float
+             (dead state)
+    */
+
+    // loop until end of string or dead state reached
+    while (state != 5 && p < len) {
+        char c = *(s + p);
+
+        switch (state) {
+            // initial state
+            case 0:
+                if (c == '0')
+                    state = 4;
+                else if (c >= '1' && c <= '9')
+                    state = 1;
+                else if (c == '.')
+                    state = 2;
+                else
+                    state = 5;
+            break;
+
+            // first digit is between 1 - 9
+            case 1:
+                if (c >= '0' && c <= '9')
+                    state = 1;
+                else if (c == '.')
+                    state = 2;
+                else
+                    state = 5;
+            break;
+
+            // decimal has been encountered
+            case 2:
+                if (c >= '0' && c <= '9')
+                    state = 3;
+                else
+                    state = 5;
+            break;
+
+            // there is atleast one digit after decimal
+            case 3:
+                if (c >= '0' && c <= '9')
+                    state = 3;
+                else
+                    state = 5;
+            break;
+
+            // first digit is 0
+            case 4:
+                if (c == '.')
+                    state = 2;
+                else
+                    state = 5;
+            break;
+        }
+
+        p++;
+    }
+
+
+    if (state == 1 || state == 4)
+        return 1;
+    else if (state == 3)
+        return 2;
+    else
+        return 0;
+}