A brief introduction to the for loop. Some of the code involves arrays

Basic format

！！for ( sentence 1; sentence 2; sentence 3) {
     Block of code to execute
}

for Monolayer cycle

General writing ：

document.write(cars[0] + "<br>");

document.write(cars[1] + "<br>");

document.write(cars[2] + "<br>");

document.write(cars[3] + "<br>");

document.write(cars[4] + "<br>");

document.write(cars[5] + "<br>");

Use for loop

for (var i=0;i<cars.length;i++) {

        document.write(cars[i] + "<br>");

}

for loop 

 Grammatical structure ：
for( Initialize variable ; Conditional expression ; Operation expression ){
   // The loop body 
}
 give an example ：
  for (var i = 1; i <= 5; i++) {
        console.log(' The number is ：' + i + '\n');
  }

Case study ： Find the sum and average of an array （ Involving arrays ）

var sum =[1,2,3,4,6,7,10]
		var o =0;
		var p = 0;
		sum[3]=55;
		
		for(var i=0;i<sum.length;i++){
				o = o +sum[i]
				console.log(sum[i])
		}p = o/sum.length

          Find the maximum value of an array （ Involving arrays ）

	var arr = [10,5,6,9,4,5];
			
			 	var i =arr[0];
			 	var w =arr[0];
			 	for(var o=0;o<arr.length;o++){
			 		if(i<arr[o]){
			 			i = arr[o]
			 		}
			 	}console.log(" Maximum "+i)

            Print inverted triangle

                var i ="";
			 	for(var k=1;k<=5;k++){
			 		for(var q=1;q<=6-k;q++){
						
	        		i = i + "*";
					}
			 		i = i +"\n";
			 	} 
			 	console.log(i);

        Print a square

            var str="";
			for(var i=1;i<=4;i++){
				
				for(var j=1;j<=4;j++){
					 str = str+"*";
				}
				str = str+"\n"
			}
			console.log(str);

        Print the multiplication table

	    var num= "";
		for(var i=1;i<=9;i++){
		for(var j=1;j<=i;j++){
		num = num + j + "*" + i +"="+ j*i + "\t";
		}		num = num + "\n";
		}console.log(num);