Having issues with my loop code and it does not work correctly?

Question

I have been asked to make a prompt to enter your current weight and target weight. The loop should calculate how many weeks it will take to reach target weight at loss of 1.38 a week. My prompts work but the loop breaks the javascript. My code is below, can someone help me out? I am new to javscript by the way.

 var current_weight = prompt("Please enter your current weight",0.0);
 var target_weight = prompt("Please enter your target weight",0.0);
 var weeks = 0;
 if(current_weight > 0 target_weight > 0){
 if(current_weight > target_weight){
 while(current_weight <= target weight){
 var current_weight = current_weight – 1.38;
 weeks = weeks + 1;
 alert("it will take" + weeks + "weeks to hit target");
 }
 }
 else if(current_weight > 0 && target_weight > 1){
 alert("Current weight must be more than target weight");
 }
 else{ 
 alert("Input error")
 }
</script>

The loop breaks the javascript.

• mjw: if current_weight > target_weight, why would the while (current_weight <= target_weight) ever evaluate to true? recheck your logic and adjust the conditions accordingly.
• IronMan: Hi interesting, so both conditions can't be true so the loop won't execute. if (current_weight > target_weight) {while( current_weight <= target weight) { ...
• Alice Oualouest: Is some logic operator missing in if(current_weight > 0 target_weight > 0){ ?

Answer 1

4 problems in your code:

• missing && operator between the conditions in first if statement

• prompt returns the user entered value as string. So you can't subtract 1.38 from current_weight as current_weight will be a string. You need to convert user entered values in to numbers

• There's a logical error in your code. You have this if statement if(current_weight > target_weight) and if it evaluates to true, then while loop checks while(current_weight <= target weight) which is opposite to the condition of the wrapping if statement. Consequently, your loop will never run. You probably want loop condition to be current_weight > target_weight

• alert should be outside the while loop

var current_weight = Number(prompt("Please enter your current weight", 0.0));
var target_weight = Number(prompt("Please enter your target weight", 0.0));
var weeks = 0;
if (current_weight > 0 && target_weight > 0) {
 if (current_weight > target_weight) {
 while (current_weight > target_weight) {
 current_weight = current_weight - 1.38;
 weeks = weeks + 1;
 }
 alert("it will take" + weeks + "weeks to hit target");
 } else if (current_weight > 0 && target_weight > 1) {
 alert("Current weight must be more than target weight");
 } else {
 alert("Input error");
 }
}