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Following table shows all the relational operators supported by Fortran. Assume variable **A** holds 10 and variable **B** holds 20, then −

Operator | Equivalent | Description | Example |
---|---|---|---|

== | .eq. | Checks if the values of two operands are equal or not, if yes then condition becomes true. | (A == B) is not true. |

/= | .ne. | Checks if the values of two operands are equal or not, if values are not equal then condition becomes true. | (A != B) is true. |

> | .gt. | Checks if the value of left operand is greater than the value of right operand, if yes then condition becomes true. | (A > B) is not true. |

< | .lt. | Checks if the value of left operand is less than the value of right operand, if yes then condition becomes true. | (A < B) is true. |

>= | .ge. | Checks if the value of left operand is greater than or equal to the value of right operand, if yes then condition becomes true. | (A >= B) is not true. |

<= | .le. | Checks if the value of left operand is less than or equal to the value of right operand, if yes then condition becomes true. | (A <= B) is true. |

Try the following example to understand all the logical operators available in Fortran −

! this program checks relational operators implicit none ! variable declaration integer :: a, b ! assigning values a = 10 b = 20 if (a .eq. b) then print *, "Line 1 - a is equal to b" else print *, "Line 1 - a is not equal to b" end if if (a > b) then print *, "Line 2 - a is greater than b" else print *, "Line 2 - a is less than b" end if if (a <= b) then print *, "Line 3 - a is less than or equal to b" else print *, "Line 3 - a is greater than b" end if a = 20 b = 20 if (a .eq. b) then print *, "Line 4 - a is equal to b" else print *, "Line 4 - a is not equal to b" end if end

When you compile and execute the above program it produces the following result −

Line 1 - a is not equal to b Line 2 - a is less than b Line 3 - a is less than or equal to b Line 4 - a is equal to b

fortran_operators.htm

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