Java For Loop
In this tutorial, we will learn how to use for
loop to perform repetitive tasks.
The for
loop is used to execute the block of codes for certain number of times.
Syntax of for loop
for(initialization; condition; increment/decrement){
// block of codes.
}
The intialization
statement is executed only once during the first execution in the for loop.
The condition
is checked to execute the block of codes if the condition is satisfied.
The increment
or decrement
statement is used to increment or decrement any value, usually the variable initialized in the initialization statement.
Example program to print sequence of n numbers
class Main {
public static void main(String[] args) {
int n = 5;
// for loop
for (int i = 1; i <= n; i++) {
System.out.println("Loop "+i);
}
}
}
Output
Loop 1
Loop 2
Loop 3
Loop 4
Loop 5
In the above program, the value of n
is initially set to 5 for running the loop 5 times.
In the for
loop, we initially set the values of i
to 1 which is the start count of the loop. In the condition, we check whether the value of i
is less than n
.
If the condition is satisfied, it will allow to enter the loop. The third statement is the increment
statement which increase the value of i
by 1 after the execution of the loop.
Example for sum of n natural numbers
class Main {
public static void main(String[] args) {
int n = 5, sum = 0;
for (int i = 1; i <= n; ++i) {
sum+=i;
}
System.out.printf("Sum of %d numbers is %d",n,sum);
}
}
Output
Sum of 5 numbers is 15
In the above program, we need to find the sum of 5 natural numbers.
Here, we initialize the value of n
to 5 and sum
to 0. The variable sum
is used to hold the sum of n
natural numbers.
In the for
loop we will initialize the value of i
to 1. Then in the condition we check whether the value of i
is less than n
.
If the condition is satisfied, we add the value of i
to sum
variable.
Finally, when the condition is not satisfied, we print the value of sum
.