Merge pull request #67 from RealCifer/RealCifer-4

Added solution for issue #48 that is question 6

solutions/sol004.c

@@ -0,0 +1,17 @@
+#include<stdio.h>
+
+int main ()
+{
+    // Defining function
+    int n;
+    printf("Enter an integer n of your choice:");
+    scanf("%d", &n);
+
+    // Writing formula to calculate the sum of first n natural number
+    int sum = ( n * ( n + 1)) / 2;
+
+    //Printing result
+    printf("Sum of the first %d natural numbers is %d\n", n, sum);
+
+    return 0;
+}

solutions/sol006.c

@@ -0,0 +1,52 @@
+#include <stdio.h>
+
+#define PI 3.141
+
+int main() {
+    int choice;
+
+    printf("Choose the desired shape :\n");
+    printf("1. Triangle\n");
+    printf("2. Rectangle\n");
+    printf("3. Circle\n");
+
+    printf("Enter your choice\n");
+    scanf("%d", &choice);
+
+    switch (choice) {
+        case 1: {
+            double base, height, area;
+            printf("Enter the base of triangle: ");
+            scanf("%lf", &base);
+            printf("Enter the height of triangle: ");
+            scanf("%lf", &height);
+            area = 0.5 * base*height;
+            printf("Area of the triangle is: %.2lf\n", area);
+            break;
+        }
+
+        case 2: {
+            double length, width, area;
+            printf("Enter the length of rectangle: ");
+            scanf("%lf", &length);
+            printf("Enter the width of rectangle: ");
+            scanf("%lf", &width);
+            area = length*width;
+            printf("Area of rectangle is: %.2lf\n", area);
+            break;
+        }
+
+        case 3: {
+            double radius, area;
+            printf("Enter the radius of circle: ");
+            scanf("%lf", &radius);
+            area = PI * radius*radius;
+            printf("Area of circle is: %.2lf\n", area);
+            break;
+        }
+        default:
+            printf("You entered wrong choice.\n");
+    }
+    return 0;
+}
+