added iterative gcd funcion

c/1darray.c

@@ -14,4 +14,4 @@ int main(){
 
 	printf("Sum=%d",sum);
 	return 0;
-}
+}

c/2darray.c

@@ -20,4 +20,4 @@ int main(){
 		}
 	}
 	return 0;
-}
+}

c/callByRef.c

@@ -32,4 +32,4 @@ void callByRef(int *x,int *y){
 	*y=*t;
 	printf("From call by value\n");
 	printf("x=%d\ty=%d\n",*x,*y);
-}
+}

c/cylinder.c

@@ -33,4 +33,4 @@ void cylinder(float r, float h, float *csa, float *tsa, float *vol){
 	*csa = 2*r*h*PI;
 	*tsa = 2*r*(h+r)*PI;
 	*vol = r*r*h*PI;
-}
+}

c/datatype.c

@@ -12,4 +12,4 @@ int main(){
 	//printing data
 	printf("%c %d %f %lf",ch,i,f,d);
 	return 0;
-}
+}

c/empstruct.c

@@ -37,4 +37,4 @@ int main(){
 	printf("\nHighest Earner Detail\n");
 	printf("Name: %s\nPost: %s\nSalary: %.2f\n",high.name,high.post,high.salary);
 	return 0;
-}
+}

c/forloop.c

@@ -4,11 +4,12 @@ int main(){
 	int i,n;
 
 	//reading value of n
+	printf("Enter n: ");
 	scanf("%d",&n);
 
 	//for loop
 	for(i=1;i<=n;i++){
 		printf("%d\n",i);
 	}
 	return 0;
-}
+}

c/hello.c

@@ -2,4 +2,4 @@
 int main(){
 	printf("Hello World");
 	return 0;
-}
+}

recursion/gcd.c

@@ -1,26 +1,50 @@
 #include <stdio.h>
+
+//recursive function for gcd of two numbers.
 int gcd(int x, int y);
 
+//iterative function for gcd of two numbers.
+int gcd_iter(int u , int v);
 int main(){
-	int a, b, g;
+	int a, b, g, f;
 
 	printf("Enter a and b:\n");
 	scanf("%d%d", &a, &b);
 
 	//gcd
 	g = gcd(a, b);
 
+	//gcd_iter
+	f=gcd_iter(a, b);
+
 	//in case g is negative, then convert it into positive
 	if(g < 0){
 		g *= -1;
 	}
 
+	//in case f is negative, then convert it into positive
+	if(f < 0){
+		f=f*(-1);
+	}
+
 	//output
-	printf("GCD(%d, %d) = %d\n", a, b, g);
+	printf("Recursive GCD(%d, %d) = %d\n", a, b, g);
+	printf("Iterative GCD(%d, %d) = %d\n", a, b, f);
 	return 0;
 }
 
 int gcd(int x, int y){
 	if(y == 0) return x;
 	else gcd(y, x%y);
-}
+}
+
+
+int gcd_iter(int u, int v){
+	int t;
+	while (v) {
+		t = u; 
+		u = v; 
+		v = t % v;
+	}
+	return u < 0 ? -u : u; /* abs(u) */
+}

recursion/towerOfHanoi.c

@@ -19,4 +19,4 @@ void t(int n, char beg, char aux, char end){
 		t(1, beg, aux, end);
 		t(n-1, aux, beg, end);
 	}
-}//t() ends here
+}//t() ends here