This tutorial focuses on the for loop. You will learn about the other type of loops in the upcoming tutorials.<\/p>\n\n\n\n
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Java for Loop<\/h2>\n\n\n\n
Java Here,<\/p>\n\n\n\n <\/p>\n\n\n\n Output<\/strong><\/p>\n\n\n\n Here is how this program works.<\/p>\n\n\n\n Output<\/strong><\/p>\n\n\n\n Here is how the program works.<\/p>\n\n\n\n Output<\/strong>:<\/p>\n\n\n\n Here, the value of sum<\/var> is 0<\/strong> initially. Then, the for loop is iterated from When i<\/var> becomes 1001<\/strong>, the test condition is The above program to add the sum of natural numbers can also be written as<\/p>\n\n\n\n The output of this program is the same as the Example 3<\/strong>.<\/p>\n\n\n\n The Java for loop has an alternative syntax that makes it easy to iterate through\u00a0arrays\u00a0and collections. For example,<\/p>\n\n\n\n Output<\/strong><\/p>\n\n\n\n Here, we have used the for-each loop<\/strong> to print each element of the numbers<\/var> array one by one.<\/p>\n\n\n\n In the first iteration of the loop, number<\/var> will be 3, number<\/var> will be 7 in second iteration and so on.<\/p>\n\n\n\n <\/p>\n\n\n\n If we set the test expression<\/strong> in such a way that it never evaluates to Here, the test expression ,for<\/code> loop is used to run a block of code for a certain number of times. The syntax of for<\/code> loop is:<\/p>\n\n\n\nfor (initialExpression;\n testExpression; \nupdateExpression) {\n \/\/ body of the loop\n}<\/code><\/pre>\n\n\n\ntrue<\/code>, the body of the for<\/code> loop is executed.<\/li>false<\/code>.<\/li><\/ol>\n\n\n\n
\n\n\n\n![\"Working](\"https:\/\/cdn.programiz.com\/sites\/tutorial2program\/files\/java-for-loop.png\" "\\"Working")
\n\n\n\nExample 1: Display a Text Five Times<\/h3>\n\n\n\n
\/\/ Program to print a text 5 times\n\nclass Main {\n public static void main(String[] args) {\n\n int n = 5;\n \/\/ for loop \n for (int i = 1; i <= n; ++i) {\n System.out.println(\"Java is fun\");\n }\n }\n}<\/code><\/pre>\n\n\n\nJava is fun\nJava is fun\nJava is fun\nJava is fun\nJava is fun<\/samp><\/code><\/pre>\n\n\n\nIteration<\/th> Variable<\/th> Condition: i <= n<\/th> Action<\/th><\/tr> 1st<\/td> i = 1<\/code>n = 5<\/code><\/td>true<\/code><\/td>Java is fun<\/samp> is printed.
i<\/var> is increased to 2<\/strong>.<\/td><\/tr>2nd<\/td> i = 2<\/code>n = 5<\/code><\/td>true<\/code><\/td>Java is fun<\/samp> is printed.
i<\/var> is increased to 3<\/strong>.<\/td><\/tr>3rd<\/td> i = 3<\/code>n = 5<\/code><\/td>true<\/code><\/td>Java is fun<\/samp> is printed.
i<\/var> is increased to 4<\/strong>.<\/td><\/tr>4th<\/td> i = 4<\/code>n = 5<\/code><\/td>true<\/code><\/td>Java is fun<\/samp> is printed.
i<\/var> is increased to 5<\/strong>.<\/td><\/tr>5th<\/td> i = 5<\/code>n = 5<\/code><\/td>true<\/code><\/td>Java is fun<\/samp> is printed.
i<\/var> is increased to 6<\/strong>.<\/td><\/tr>6th<\/td> i = 6<\/code>n = 5<\/code><\/td>false<\/code><\/td>The loop is terminated.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
\n\n\n\nExample 2: Display numbers from 1 to 5<\/h3>\n\n\n\n
\/\/ Program to print numbers from 1 to 5\n\nclass Main {\n public static void main(String[] args) {\n \n int n = 5;\n \/\/ for loop \n for (int i = 1; i <= n; ++i) {\n System.out.println(i);\n }\n }\n}<\/code><\/pre>\n\n\n\n1\n2\n3\n4\n5<\/samp><\/code><\/pre>\n\n\n\nIteration<\/th> Variable<\/th> Condition: i <= n<\/th> Action<\/th><\/tr> 1st<\/td> i = 1<\/code>n = 5<\/code><\/td>true<\/code><\/td>1<\/samp> is printed.
i<\/var> is increased to 2<\/strong>.<\/td><\/tr>2nd<\/td> i = 2<\/code>n = 5<\/code><\/td>true<\/code><\/td>2<\/samp> is printed.
i<\/var> is increased to 3<\/strong>.<\/td><\/tr>3rd<\/td> i = 3<\/code>n = 5<\/code><\/td>true<\/code><\/td>3<\/samp> is printed.
i<\/var> is increased to 4<\/strong>.<\/td><\/tr>4th<\/td> i = 4<\/code>n = 5<\/code><\/td>true<\/code><\/td>4<\/samp> is printed.
i<\/var> is increased to 5<\/strong>.<\/td><\/tr>5th<\/td> i = 5<\/code>n = 5<\/code><\/td>true<\/code><\/td>5<\/samp> is printed.
i<\/var> is increased to 6<\/strong>.<\/td><\/tr>6th<\/td> i = 6<\/code>n = 5<\/code><\/td>false<\/code><\/td>The loop is terminated.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
\n\n\n\nExample 3: Display Sum of n Natural Numbers<\/h3>\n\n\n\n
\/\/ Program to find the sum of natural numbers from 1 to 1000.\n\nclass Main {\n public static void main(String[] args) {\n \n int sum = 0;\n int n = 1000;\n\n \/\/ for loop\n for (int i = 1; i <= n; ++i) {\n \/\/ body inside for loop\n sum += i; \/\/ sum = sum + i\n }\n \n System.out.println(\"Sum = \" + sum);\n }\n}<\/code><\/pre>\n\n\n\nSum = 500500<\/samp><\/pre>\n\n\n\n
i = 1 to 1000<\/code>. In each iteration, i<\/var>is added to sum<\/var> and its value is increased by 1<\/strong>.<\/p>\n\n\n\nfalse<\/code> and sum<\/var> will be equal to 0 + 1 + 2 + .... + 1000<\/code>.<\/p>\n\n\n\n
\n\n\n\n\/\/ Program to find the sum of natural numbers from 1 to 1000.\n\nclass Main {\n public static void main(String[] args) {\n \n int sum = 0;\n int n = 1000;\n\n \/\/ for loop\n for (int i = n; i >= 1; --i) {\n \/\/ body inside for loop\n sum += i; \/\/ sum = sum + i\n }\n \n System.out.println(\"Sum = \" + sum);\n }\n}<\/code><\/pre>\n\n\n\n
\n\n\n\nJava for-each Loop<\/h2>\n\n\n\n
\/\/ print array elements \n\nclass Main {\n public static void main(String[] args) {\n \n \/\/ create an array\n int[] numbers = {3, 7, 5, -5};\n \n \/\/ iterating through the array \n for (int number: numbers) {\n System.out.println(number);\n }\n }\n}\n<\/code><\/pre>\n\n\n\n3\n7\n5\n-5\n<\/samp><\/code><\/pre>\n\n\n\n
\n\n\n\nJava Infinite for Loop<\/h3>\n\n\n\n
false<\/code>, the for<\/code> loop will run forever. This is called infinite for loop. For example,<\/p>\n\n\n\n\/\/ Infinite for Loop\n\nclass Infinite {\n public static void main(String[] args) {\n \n int sum = 0;\n\n for (int i = 1; i <= 10; --i) {\n System.out.println(\"Hello\");\n }\n }\n}<\/code><\/pre>\n\n\n\ni <= 10<\/code>, is never false<\/code> and Hello<\/code> is printed repeatedly until the memory runs out.<\/p>\n\n\n\n<\/a><\/h3>\n\n\n\n