Sum pervious values of total with each iteration - Angular JS

Question

I have a controller of Angular JS which sum numbers of values with the help of range loop but now I have requirement need to sum previous value of total with each iteration. I have tried with so many filters but no success. I have require desired result. Helps are definitely appreciated.

var arr = [
  {
    "unique_id": "CS",
    "college": "BSCS",
    "arr_length": 1,
    "program_section": [
      {
        "question": "Q1",
        "total": 135,
        
      },
      {
        "question": "Q2",
        "total": 142,
        
      },
      {
        "question": "Q3",
        "total": 135,
        
      },
      {
        "question": "Q4",
        "total": 137,
        
      },
      
    ]
  },
  {
    "unique_id": "MBA",
    "college": "BBA",
    "arr_length": 2,
    "program_section": [
      {
        "question": "Q1",
        "total": 175,
        
      },
      {
        "question": "Q2",
        "total": 142,
        
      },
      {
        "question": "Q3",
        "total": 165,
        
      },
      {
        "question": "Q4",
        "total": 137,
        
      },
      
    ]
  },
  {
    "unique_id": "CA",
    "college": "Account",
    "arr_length": 1,
    "program_section": [
      {
        "question": "Q1",
        "total": 145,
        
      },
      {
        "question": "Q2",
        "total": 162,
        
      },
      {
        "question": "Q3",
        "total": 125,
        
      },
      {
        "question": "Q4",
        "total": 117,
        
      },
      
    ]
  }
];
var app = angular.module('myApp', []);
app.controller('customersCtrl', function($scope, $http) {
    $scope.names = arr;
}).filter('range', function() {
  return function(input, total) {
    total = parseInt(total);

    for (var i=0; i<total; i++) {
      input.push(i);
    }

    return input;
  };
});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="myApp" ng-controller="customersCtrl"> 

<table  border="1">
<thead>
  <tr>
    <td>Question</td>
    <td ng-repeat="x in names">{{ x.college }}</td>
  </tr>
</thead>
<tbody>
      <tr ng-repeat="n in [] | range:4">
        <td>
            {{ names[0].program_section[n].question }}
        </td>
        <td width="100px" ng-repeat="x in names">
           {{ x.program_section[n].total }}
        </td>
      </tr>
</tbody>
  
</table>

</div>

Desired Result

<table width="426" border="1">
  <tr>
    <td width="79">Question</td>
    <td >BSCS</td>
    <td >BBA</td>
    <td >Account</td>
    <td >Total</td>
  </tr>
  <tr>
    <td>Q1</td>
    <td>135</td>
    <td>175</td>
    <td>145</td>
    <td width="50" >455</td>
  </tr>
  <tr>
    <td>Q2</td>
    <td>142</td>
    <td>142</td>
    <td>162</td>
    <td width="50" >446</td>
  </tr>
  <tr>
    <td>Q3</td>
    <td>135</td>
    <td>165</td>
    <td>125</td>
    <td width="50" >425</td>
  </tr>
  <tr>
    <td>Q4</td>
    <td>137</td>
    <td>137</td>
    <td>117</td>
    <td width="50" >391</td>
  </tr>
</table>

Answer 1

You could just calculate the totals in the controller and use that to generate remaining column:

$scope.totals = {}
    arr.map(function(obj){
        obj.program_section.map(function(section){
            $scope.totals[section.question] = ($scope.totals[section.question] || 0) + section.total
        })
    })

Here totals[Qx] will have totals for Qx, and we use that in the view:

var arr = [
  {
    "unique_id": "CS",
    "college": "BSCS",
    "arr_length": 1,
    "program_section": [
      {
        "question": "Q1",
        "total": 135,
        
      },
      {
        "question": "Q2",
        "total": 142,
        
      },
      {
        "question": "Q3",
        "total": 135,
        
      },
      {
        "question": "Q4",
        "total": 137,
        
      },
      
    ]
  },
  {
    "unique_id": "MBA",
    "college": "BBA",
    "arr_length": 2,
    "program_section": [
      {
        "question": "Q1",
        "total": 175,
        
      },
      {
        "question": "Q2",
        "total": 142,
        
      },
      {
        "question": "Q3",
        "total": 165,
        
      },
      {
        "question": "Q4",
        "total": 137,
        
      },
      
    ]
  },
  {
    "unique_id": "CA",
    "college": "Account",
    "arr_length": 1,
    "program_section": [
      {
        "question": "Q1",
        "total": 145,
        
      },
      {
        "question": "Q2",
        "total": 162,
        
      },
      {
        "question": "Q3",
        "total": 125,
        
      },
      {
        "question": "Q4",
        "total": 117,
        
      },
      
    ]
  }
];
var app = angular.module('myApp', []);
app.controller('customersCtrl', function($scope, $http) {
    $scope.names = arr;
    $scope.totals = {}
    arr.map(function(obj){
        obj.program_section.map(function(section){
            $scope.totals[section.question] = ($scope.totals[section.question] || 0) + section.total
        })
    })
}).filter('range', function() {
  return function(input, total) {
    total = parseInt(total);

    for (var i=0; i<total; i++) {
      input.push(i);
    }

    return input;
  };
});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="myApp" ng-controller="customersCtrl"> 

<table  border="1">
<thead>
  <tr>
    <td>Question</td>
    <td ng-repeat="x in names">{{ x.college }}</td>
    <td>Totals</td>
  </tr>
</thead>
<tbody>
      <tr ng-repeat="n in [] | range:4">
        <td>
            {{ names[0].program_section[n].question }}
        </td>
        <td width="100px" ng-repeat="x in names" >
           {{ x.program_section[n].total }}
        </td>
        <td width="50%" ng-bind="totals[names[0].program_section[n].question]"></td>
      </tr>
      
</tbody>
  
</table>

</div>