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Control statements

Control statements in Java are actually the same as C and will involve knives including if-else, while, do-while, for, return, break, switch.

Conditional statements​

if statements​

int a = 10;

if(a > 10){
 return true;
}

return false;

if.. .else statement​

int a = 10;
int b = 11;

if(a >= b){
 System.out.println("a >= b");
}else{
 System.out.println("a < b");
}

if.. .else if Multi-branch statements​

int x = 40;

if(x > 60) {
 System.out.println("The value of x is greater than 60");
} else if (x > 30) {
 System.out.println("The value of x is greater than 30 but less than 60");
} else if (x > 0) {
 System.out.println("The value of x is greater than 0 but less than 30");
} else {
 System.out.println("The value of x is less than or equal to 0");
}

switch multi-branch statement​

switch (week) {
 case 1:
  System.out.println("Monday");
  break;
 case 2:
        System.out.println("Tuesday");
        break;
 case 3:
        System.out.println("Wednesday");
        break;
 case 4:
        System.out.println("Thursday");
        break;
 case 5:
        System.out.println("Friday");
        break;
 case 6:
        System.out.println("Saturday");
        break;
 case 7:
        System.out.println("Sunday");
        break;
 default:
        System.out.println("No Else");
        break;
}

Loop statements​

while loop statement​

while (boolean) {
 expression
}

do... .while loop statement​

The only difference between a while and a do... ...while loop is that the do... while statement is executed at least once.

int b = 10;
do {
 System.out.println("b == " + b);
 b--;
} while(b == 1);

for loop statement​

for(initialize; Boolean expression; step) {}

The boolean expression is tested before each iteration, and if the result obtained is false, the code following the for statement is executed; at the end of each loop, the next loop is executed according to the value of the step.

Comma operator​

A series of comma-separated statements can be used in the initialisation part of a for statement expression; the comma operator allows multiple variables to be defined within a for statement.

for(int i = 1; j = i + 10;i < 5;i++, j = j * 2){}

for-each statement​

The for-each statement is a more introductory and convenient way of traversing arrays and collections.

int array[] = {7, 8, 9};

for (int arr : array) {
 System.out.println(arr);
}

Jump statements​

break statement​

Terminates the loop

continue statement​

Leaves the current loop and executes the next one.

return statement​

The return statement