# Can you have a DO loop inside a DO loop?

## Can you have a DO loop inside a DO loop?

One way to make iterative DO loops even more powerful is to place one DO loop inside of another. Putting a DO loop within another DO loop is called nesting.

### What is nested DO loop in FORTRAN?

Just like an IF-THEN-ELSE-END IF can contain another IF-THEN-ELSE-END IF (see nested IF for the details), a DO-loop can contain other DO-loops in its body. The body of the contained DO-loop, usually referred to as the nested DO-loop, must be completely inside the containing DO-loop.

#### What is nested DO loop?

If the LEAVE instruction is for the inner loop, you leave the inner loop and go to the outer loop. If the LEAVE instruction is for the outer loop, you leave both loops.

What rules apply to the nesting of loops?

In a nested loop, a break statement only stops the loop it is placed in. Therefore, if a break is placed in the inner loop, the outer loop still continues. However, if the break is placed in the outer loop, all of the looping stops.

Why DO loop is used in FORTRAN?

The do loop construct enables a statement, or a series of statements, to be carried out iteratively, while a given condition is true.

## How do you exit a loop in FORTRAN?

Exit statement terminates the loop or select case statement, and transfers execution to the statement immediately following the loop or select.

### Can while loop be nested?

What Is a Nested While Loop? A nested while loop is a while statement inside another while statement. Once the condition of the inner loop is satisfied, the program moves to the next iteration of the outer loop.

#### Can a for loop be nested in a while loop?

The loop which contains a loop inside a loop is known as the nested loop. It can contain the for loop inside a for loop or a while loop inside a while loop. It is also possible that a while loop can contain the for loop and vice-versa.

What is the use of implicit none in FORTRAN?

The implicit none statement is used to inhibit a very old feature of Fortran that by default treats all variables that start with the letters i, j, k, l, m and n as integers and all other variables as real arguments. Implicit None should always be used.

How do you break a loop in FORTRAN?

## What kinds of loops can be nested?

The most common applications of loops are for matrix data (e.g., looping through the rows and columns of a table). You can nest any type of loop inside any other type; a for loop can be nested in a while loop.

### Which one is an example of nested loops loop within another loop?

If a loop exists inside the body of another loop, it’s called a nested loop. Here’s an example of the nested for loop. // outer loop for (int i = 1; i <= 5; ++i) { // codes // inner loop for(int j = 1; j <=2; ++j) { // codes } .. } Here, we are using a for loop inside another for loop.

#### Why does Fortran return 0 when I Divide by 3?

Something odd is happening. The problem is the line: FORTRAN evaluates the right hand side of the assignment first using integer arithmetic, because both x and 3 are integer. 1 divided by 3 cannot be stored as an integer, and so the value 0 is returned. The result, 0, is then converted to a real number and the assigned to y.

How does Fortran calculate the result in stages?

where x and y are real and i is integer, FORTRAN computes the result in stages: First it calculates (2**i)/3 and evaluates it as an integer number, then multiplies the result by x and evaluates it as real.

What was the mistake in the DO loop in F77?

The tracking system program was written in F77, and there was a typo in the DO loop: the comma (,) was mistakenly typed as a period (.) Guess what the new F77 program did…

## How do I use Fortran to calculate the right hand side?

FORTRAN is keeping the integer part of the answer and throwing the rest away. To get over this problem, we have to signal to FORTRAN that we want it to calculate the right hand side of the expression using real arithmetic. If we want to keep x as integer data type, we could re-write our expression as follows: y=x/3.0