If statement

এখন আমরা শিখব কিভাবে If statement এর সাহায্যে Fortran এ একটি problem  solve করা যায়।

What is if statement ?

             If statement এ্কটি conditional statement যা একটি statement বা একটি arithmetic expression সত্য আথবা অসত্য নির্দেষ করে।

সাধারণত তিন ধরণের if statement পাওয়া যায়।

1.    logical if statement

2.    Block if statement

3.    Arithmetic if statement

How to solve a problem in Force2.0

Find the sum of the series by using if statement

Y=1+2+3+………….+N

Solution             

1234567890

                 Print*, ‘enter the value of n’

                 Read*, n

                 K=1

                 Sum = 0.0

10                           sum =sum + k

k=k+1    

if (k .le. n)   go to 10

print*, ‘the value of the result is ‘

print*, sum

 End

It’s works like as do statement . Here we use the  if statement if(k.le.n) means that , if k  less then equal n then  go to 10 , 10 is the statement level . And the statement (sum =sum+k) is defined as the level 10. The procedure will continue until k is less then equal n .i.e k=1,2,3,4…………..<= n. if k is > n then the process will be brought to path of end.

**Let’s do another problem

Given that

Values of  x	Result
5.65	The value of x is less then 10
8.45	The value of x is less then 10
12.7	The value of Y is = 17.9005585
21.65	The value of Y is = 48.869709
15.7	The value of Y is = 26.5071354

Given the formula  

 Then calculate Y if  x greater then 10  and if x is less then 10 then print ‘ the value of x is less then 10’

Solution

1234567890

               Do N = 1,5

                Write(*,*) ‘Enter the value of x’

                Read(*,*) x

                 If( x .gt. 10) then

                 Y=sqrt(x**0.45)+(x**2/10)

                 Print*, ‘The value of Y is = ‘, Y

                 Else

                 Print*, ‘The value of x is less then 10’

                  End if

                  End do

                 End

Description:

Here is use do statement because we have 5 values of x so N = 1, 5 as the program run 5 times for each values of x. We have to remind that do statement must be stop by the statement End do and If statement must be stop by End if statement.

If you try more you can learn more.