Simple PHP calculator

Question

I m creating a basic PHP calculator that lets you enter two values and chose your operator then displays the answer  Everything is working fine except it s not outputting the answer to the browser   Here are the codes for my html and PHP files                lt head gt   lt meta charset  utf-8  gt   lt title gt Calculator lt  title gt   lt  head gt   lt body gt   lt form method  post  attribute  post  action  disp form php  gt   lt p gt First Value  lt br  gt   lt input type  text  id  first  name  first  gt  lt  p gt   lt p gt Second Value  lt br  gt   lt input type  text  id  second  name  second  gt  lt  p gt   lt input type  radio  name  group1  id  add  value  add  checked  true  gt  lt p gt   lt  p gt  lt br  gt   lt input type  radio  name  group1  id  subtract  value  subtract  gt  lt p gt - lt  p gt  lt br  gt   lt input type  radio  name  group1  id  times  value  times  gt  lt p gt x lt  p gt  lt br  gt   lt input type  radio  name  group1  id  divide  value  divide  gt  lt p gt   lt  p gt  lt br  gt   lt p gt  lt  p gt   lt button type  submit  name  answer  id  answer  value  answer  gt Calculate lt  button gt   lt  form gt   lt  body gt   lt  html gt    PHP file    lt  doctype html gt   lt html gt   lt head gt   lt meta charset  utf-8  gt   lt title gt Answer lt  title gt   lt  head gt   lt body gt   lt p gt The answer is    lt  php if   POST  group1      add    echo   first    second     else if   POST  group1      subtract    echo   first -  second     else if   POST  group1      times    echo   first    second     else   POST  group1      divide    echo   first    second       gt   lt  p gt    lt  body gt   lt  html gt

User · Answer

You need to get the values the same way to get the calculator operation which looks like:

<?php
if($_POST['group1'] == add) {
echo "$_POST['first']+ $_POST['second'];
}
... and so on
?>

Or, to make it easier, just do:

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Answer</title>
</head>
<body>
<p>The answer is: 
<?php
$first = $_POST['first'];
$second= $_POST['second'];

if($_POST['group1'] == add) {
echo "$first + $second";
}
else if($_POST['group1'] == subtract) {
echo "$first - $second";
}
else if($_POST['group1'] == times) {
echo "$first * $second";
}
else($_POST['group1'] == divide) {
echo "$first / $second";
}
?>
</p> 
</body>
</html>

User · Answer

lt  DOCTYPE html gt       lt html lang  en  gt       lt head gt           lt meta charset  UTF-8  gt           lt title gt Calculator lt  title gt       lt  head gt       lt body gt      HTML Code is here             lt form method  post  gt               lt input type  text  name  numb1  gt               lt input type  text  name  numb2  gt               lt select name  operator  id    gt                  lt option gt None lt  option gt                  lt option gt Add lt  option gt                  lt option gt Subtract lt  option gt                  lt option gt Multiply lt  option gt                  lt option gt Divide lt  option gt                  lt option gt Square lt  option gt               lt  select gt               lt button type  submit  name  submit  value  submit  gt Calculate lt  button gt            lt  form gt       PHP Code            lt  php               if  isset   POST  submit                        result1     POST  numb1                     result2     POST  numb2                     operator     POST  operator                    switch   operator                        case  None                           echo  You need to select any operator                           break                      case  Add                           echo  result1    result2                          break                      case  Subtract                           echo  result1 -  result2                          break                      case  Multiply                           echo  result1    result2                          break                      case  Divide                           echo  result1    result2                          break                      case  Square                           echo  result1     result2                          break                                               gt          enter code here       lt  body gt       lt  html gt

User · Answer

Make this changes in php file    lt html gt   lt head gt   lt meta charset  utf-8  gt   lt title gt Answer lt  title gt   lt  head gt   lt body gt   lt p gt The answer is    lt  php  first     POST  first     second    POST  second    if   POST  group1       add     echo  first    second    else if   POST  group1       subtract     echo  first -  second    else if   POST  group1       times     echo  first    second     else if   POST  group1       divide     echo  first    second    else       echo  Enter the numbers properly       gt   lt  p gt    lt  body gt   lt  html gt

User · Answer

You need to assign  first and  second   first     POST  first     second    POST  second      Also  As Travesty3 said  you need to do your arithmetic outside of the quotes   echo  first    second

User · Answer

Check string using single quotes  Ex    POST  group1       add

User · Answer

lt  php  cal1    GET  cal1     cal2    GET  cal2     symbol    GET  symbol      if  symbol                add    cal1    cal2      echo  Addition is    add     else if  symbol     -          subs    cal1 -  cal2      echo  Substraction is    subs      else if  symbol                mul    cal1    cal2      echo  Multiply is    mul     else if  symbol                div    cal1    cal2      echo  Division is    div       else        echo  Oops  something wrong in your code son         gt

User · Answer

lt  DOCTYPE html gt   lt html lang  en  dir  ltr  gt       lt head gt           lt meta charset  utf-8  gt           lt title gt Calculator lt  title gt        lt  head gt   lt body gt        lt form method  GET  gt       lt h1 gt Calculator lt  h1 gt       lt p gt This is a calculator made by Hau Teen Yee Fabrice and is free to use  lt  p gt           lt ul gt        lt ol gt  Multiplication     lt  ol gt        lt ol gt  Substraction  -  lt  ol gt        lt ol gt  Division     lt  ol gt        lt ol gt  Addition     lt  ol gt           lt  ul gt        lt p gt Enter first number  lt  p gt           lt input type  text  name  cal1  gt           lt p gt Enter second number  lt  p gt           lt input type  text  name  cal2  gt           lt p gt Enter the calculator symbol lt  p gt           lt input type  text  name  symbol  gt           lt button gt Calculate lt  button gt       lt  form gt       lt  php      cal1    GET  cal1         cal2    GET  cal2         symbol    GET  symbol         if  symbol                        add    cal1    cal2          echo  Addition is    add            else if  symbol     -                  subs    cal1 -  cal2          echo  Substraction is    subs             else if  symbol                        mul    cal1    cal2          echo  Multiply is    mul            else if  symbol                        div    cal1    cal2          echo  Division is    div              else                echo  Oops  something wrong in your code son               gt       lt  body gt    lt  html gt

User · Answer

lt  php   result       class calculator       var  a      var  b       function checkopration  oprator                switch  oprator                        case                  return  this- gt a    this- gt b              break               case  -               return  this- gt a -  this- gt b              break               case                  return  this- gt a    this- gt b              break               case                  return  this- gt a    this- gt b              break               default              return  Sorry No command found                          function getresult  a   b   c                 this- gt a    a           this- gt b    b          return  this- gt checkopration  c             cal   new calculator    if isset   POST  submit               result    cal- gt getresult   POST  n1     POST  n2     POST  op         gt    lt form method  post  gt   lt table align  center  gt       lt tr gt           lt td gt  lt strong gt  lt  php echo  result    gt  lt strong gt  lt  td gt       lt  tr gt       lt tr gt           lt td gt Enter 1st Number lt  td gt           lt td gt  lt input type  text  name  n1  gt  lt  td gt       lt  tr gt        lt tr gt           lt td gt Enter 2nd Number lt  td gt           lt td gt  lt input type  text  name  n2  gt  lt  td gt       lt  tr gt        lt tr gt           lt td gt Select Oprator lt  td gt           lt td gt  lt select name  op  gt               lt option value     gt   lt  option gt               lt option value  -  gt - lt  option gt               lt option value     gt   lt  option gt               lt option value     gt   lt  option gt           lt  select gt  lt  td gt       lt  tr gt        lt tr gt           lt td gt  lt  td gt           lt td gt  lt input type  submit  name  submit  value                                     gt  lt  td gt       lt  tr gt    lt  table gt   lt  form gt

User · Answer

first   doubleval   POST  first      second   doubleval   POST  second      if   POST  group1       add         echo   first    second       first    second         etc

User · Answer

Personally I would do a switch instead of all this if  else if  else   first     POST  first     0   a small  hack  to make sure its an int but allow negs    second    POST  second     0   operator     POST  group1    switch  operator        case  add      echo  Answer is      first    second      break       case  subtract      echo  Answer is      first -  second      break      case  times      echo  Answer is      first    second      break       case  divide      echo  Answer is      first    second      break

User · Answer

You also need to put the      add   math operation into quotes  if   POST  group1       add     echo  first    second      complete code schould look like that     lt  php  first     POST  first     second    POST  second    if   POST  group1       add     echo  first    second    else if   POST  group1       subtract     echo  first -  second    else if   POST  group1       times     echo  first    second     else if   POST  group1       divide     echo  first    second      gt

[php] Simple PHP calculator

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