chore(C): added bit-manipulation (#348)

Co-authored-by: ven0m-hue <venkatesh17nayak@gmail.com>

algorithms/C/README.md

@@ -4,6 +4,11 @@
 - [Even and Odd](arrays/even-and-odd.c)
 - [Unique Elements in an array](arrays/unique-elements-in-an-array.c)
 
+## Bit Manipulation
+- [Add and Subtract](bit-manipulation/add-and-sub-bitwise)
+- [Multiply](bit-manipulation/multiply-bitwise)
+- [divide](bit-manipulation/divide-bitwise)
+
 ## Graphs
 - [Prim's Algorithm](graphs/Prim's-algorithm.c)
 

algorithms/C/bit-manipulation/add-and-sub-bitwise.c

@@ -0,0 +1,50 @@
+// function to add, sub without using the operators 
+
+#include <stdio.h>
+
+// Prototypes
+int add(int, int);
+int sub(int, int);
+
+
+int main() {
+
+	int a, b;
+
+	printf("Enter two integers\n");
+
+	scanf("%d %d", &a, &b);
+
+	int s,d;
+
+	d = add(a,b);
+
+	s = sub(a,b);
+
+	printf("%d %d",s,d);  // output 2 and 10
+
+	return 0;
+}
+
+// function to add 
+int add(int a, int b)
+{
+    int c = 0; //carry	
+	while(b !=0)
+	{
+	    c = a&b;
+	    a = a^b;
+	    b = c<<1;
+	} 
+	
+	return a;
+}
+
+// function to sub
+int sub(int a, int b) 
+{
+    int s,d;
+    d = add((~b),1);
+    s = add(a,d);
+    return s;
+} // subtraction is addition in disguise (just flip the subtracting term and that's what this function does.) 

algorithms/C/bit-manipulation/divide-bitwise.c

@@ -0,0 +1,37 @@
+// Program to divide a number without using the operator '/'
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int division(int A, int B);
+
+int main() {
+	// your code goes here
+	int a, b;
+	printf("Enter the two integers");
+	scanf("%d %d", &a, &b);
+	printf("The division is %d",division(a,b)); // Returns the floored output.
+}
+
+int division(int divisor, int dividend)
+{
+    int a = abs(divisor);
+    int b = abs(dividend);
+    int result = 0;
+    while(a-b>=0)
+    {   
+        int x=0; // b<<0
+        
+        while(a -(b<<x<<1)>=0)
+        {
+            x++;
+        }
+        
+        result += 1<<x;
+        a -= b<<x;
+    }
+    
+    return (divisor>0) == (dividend>0) ? result : -result ;
+    
+    
+}

algorithms/C/bit-manipulation/multiply-bitwise.c

@@ -0,0 +1,30 @@
+// Shift and add algo for multiplication without using multiplication operator 
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int main() {
+
+
+	// your code goes here
+	int mA, mB;
+	printf("Enter the two inputs\n");
+	scanf("%d %d", &mA, &mB);
+	int a = 0, m0 = 0,  m1 = 0;
+	m0 = mA > 0 ? mA : abs(mA);  // negative input.
+	m1 = mB > 0 ? mB : abs(mB);
+	
+    while(m1)
+    {
+        if((m1 & 0x01))   
+            a += m0;
+        
+        m0 <<= 1;
+        m1 >>= 1;
+    }
+	if(mA < 0 || mB < 0)   
+	    a = -a;
+	    
+	printf("The product is %d", a); 
+	return 0;
+}