pattern ques update

Author: INDRESH-009

js_notes/cohert1-v1.js

@@ -31,16 +31,16 @@ console.log(sum);
 
 //Question2
 //Print fibonacci series - it is a series of number where every number is the sum of the preceeding 2 numbers
-let t1 = 0,t2=1;
-let terms = 10;
-let nextterm;
-console.log(t1);
+let t1 = 0,t2=1;  //t1 and t2 are always same
+let terms = 10;  //no.of fibonacci terms required
+let nextterm;    //declaring  the nextterm variable
+console.log(t1); //logging t1 and t2 in console
 console.log(t2);
-for(let i=3;i<=terms;++i){
+for(let i=3;i<=terms;++i){  //iterating form term 3 
     nextterm = t1+t2
-    console.log(nextterm);
+    console.log(nextterm);  //once printed we change t1 to t2 and t2 to nextterm.
     t1 = t2;
     t2 = nextterm;
-    nextterm = t1+t2;
+    nextterm = t1+t2;       //now add the new 2 preceding terms 
 }
 

js_notes/patternQ.js

@@ -1,13 +1,223 @@
-//Square star pattern in js -(5 x 5)
-/* 
-    *****
-    *****
-    *****
+//loops in javascript 
+//Q1 = sum of first 10 numbers
+let sum=0;
+for(let i=0;i<=10;i++){
+    sum += i;
+}
+console.log(sum);
+
+
+//Q2 = print all even numbers from 1 to 10
+//using for loop
+for(let j=0;j<=10;j++){
+    j%2==0?console.log(j):"" 
+    //in terenary operator syntax is [condition ? execute_if_true:else statements] 
+    //if you dont have any else block you still have to complete the syntax using "" as above 
+}
+//using while loop
+let num = 0;
+while(num<=10){
+    num%2==0 ? console.log(num) : ""
+    num++;
+}
+
+//Q3 = find factorial of the number upto 10
+//do in in a for loop
+let factorial = 1;
+for(let i=1;i<=5;i++){
+    factorial *= i;
+}
+console.log(factorial);
+
+//make it as a function named calcfactorial 
+function calcfactorial (terms){
+    let ans = 1;
+    for(let i=1;i<=terms;i++){
+        ans *= i;
+    }
+    console.log(ans);
+}
+console.log(calcfactorial(5));
+
+
+//Understanding nested loops 
+/* nested loops are loops that are embedded into one another . Each time the outer loop runs and comes to the inner loop , the inner loop completes complete iteration and then goes back to outer loop. This process takes place until the outer loop is fully iterated */
+
+//Example to understand this phenomena
+for(let i=1;i<=2;i++){
+    for(let j=1;j<=3;j++){
+        console.log(`outerloop iteration no.${i} : innierloop iteration no.${j}`);
+    }
+}
+
+
+
+//Print a pattern if starts using nested loops 
+/* require output pattern
+
+*
+**
+***
+****
+
+*/
+for(let i=0;i<=4;i++){
+    let  pattern = ""   //creates an empty line after each iteration
+    for(let j=0;j<=i;j++){  //flls the no.of stars on the empty line based on the row.no (i)
+        pattern += "*";
+    }
+    console.log(pattern);
+}
+
+console.log('\n'); //escape sequence
+
+
+//Print a pattern of starts using nested loops 
+/* require output pattern
+
+******
+******
+******
+******
+******
+
+*/
+for(let i=0;i<=4;i++){
+    let pattern = "";   //starts each line as a empty string
+    for(let j=0;j<=5;j++){  //prints 6 stars on each line
+        pattern += "*";
+    }
+    console.log(pattern);
+}
+
+console.log('\n');  //escape sequence 
+
+//Print a pattern of starts using nested loops 
+/* require output pattern
+
+******
+*****
+****
+***
+**
+*
+
+*/
+for(let i=5;i>=0;i--){  //since we require a inverted triangle we are initiasing i from and  continuing the iteration till i reaches 0 by decrementing it as i--
+    let pattern = "";
+    for(let j=0;j<=i;j++){
+        pattern += "*";
+        
+    }
+    console.log(pattern); 
+}
+
+
+//Print a pattern of starts using nested loops 
+/* require output pattern
+
+     *
+    **
+   ***
+  ****
+ *****
+
+ To create a right triangle pattern in javascript you will have to deal with 3 loops, 1 of which is external and 2 are internal. The external loop will execute internal loops for 'n' number of times and the internal loop will design a pattern for each row.
+
+From the above pattern, you can see each row has a series of stars and spaces. The number of stars in a row starts from 1 preceding with 'n-1' spaces and ends with 'n' star and 0 spaces.
+
+Create 2 internal loops, 1st print n - i spaces and 2nd print i stars, where i is the number of times the external loop is executed.
+
+*/
+let row=5;
+for(let i=0;i<row;i++){
+    let pattern="";
+    for(let j=0;j<row-i;j++){
+        pattern += " " ;
+    }
+    for(let k=0;k<=i;k++){
+        pattern += "*";
+    }
+    console.log(pattern);
+}
+
+//Print a pattern of starts using nested loops 
+/* require output pattern
+      *
+     ***
     *****
+*/
+let x=3;
+
+//initalising the outer loop
+for(let i=1;i<=x;i++){
+    let pattern = "";
+    //loop for spacing viz x-i 
+    for(let j=1;j<=x-i;j++){
+        pattern += " ";
+    }
+    //loop for creating stars viz odd no. per row (2*i-1)
+    for(let k=1;k<=2*i-1;k++){
+        pattern += "*";
+    }
+    console.log(pattern);
+}
+
+//Print a pattern of starts using nested loops 
+/* require output pattern
+      *
+     ***
     *****
+   *******
+  *********
 */
-for(let i=0;i<5;i++){
-    for(let j=0;j<=i;j++){
-        console.log("*");
+
+let n = 5;
+let string = "";
+ //External loop
+for (let i = 1; i <= n; i++) {
+  // printing spaces
+  for (let j = 1; j <= n - i; j++) {
+    string += " ";
+  }
+  // printing star
+  for (let k = 0; k < 2 * i - 1; k++) {
+    string += "*";
+  }
+  string += "\n";
+}
+console.log(string);
+
+
+//Print a pattern of starts using nested loops 
+/* require output pattern
+    * * * * *
+    *       *
+    *       *
+    *       *
+    * * * * *
+    
+
+Steps to create a hollow square star pattern are:
+
+Create a variable to store the string and assign it with an empty string
+Create a for loop to run for 'n' number of times, where 'n' is number of rows/columns in the square, i.e for(let i = 0; i < n; i++)
+Inside the loop, create a for loop that prints a star (*) at the beginning and end of the line and space in between
+Also, keep in mind that the first and last row should have only stars
+Add a new line after each row
+
+*/
+let rows = 5;
+for(let i=1;i<=rows;i++){
+    let pattern = "";
+    for(let j=1;j<=rows;j++){
+        if(i==1||i==rows||j==1||j==rows){
+            pattern += "*";
+        }
+        else{
+            pattern += " ";
+        }
     }
+
+    console.log(pattern);
 }