For Loops

• To perform repeated actions , to automate tasks

​

Types of Loops

• The for loop
  •   for (statement 1 ; statement 2 ; statement 3) {
              // code to be executed
          }
    
  • statement 1 is executed one time
  • statement 2 is condition based on which loop runs
  • statement 3 is executed everytime the loop body gets executed
  •   // Program to add first n natural numbers
      let sum = 0 ;
      let n = 100;
    
      for (let i = 1 ; i <= n ; i ++) {
    
          console.log(i);
          sum += i ;
          console.log("sum of first "+ i +" Natural number is", sum);
      }
    
• For in Loop
  • works on objects and arrays
  •   // For in loop
    
      let obj = {
          kalyan : 10,
          kiran : 8,
          suma : 5,
          raj : 9
      }
      for (let a in obj) {
          console.log("Keys of obj are " + a + ", Values are " + obj[a]);
      }
    
• For off loop
  • works on strigs and arrays , they should be iterable
  •   // For off loop th obj should be iterarable like string or array
      // Works on arrays and strings
      for (let b of "kalyan") {
          console.log(b);
      }