Tag: column

C Program To Print Matrix using Nested For Loop

Lets write a simple C program to print/display a 3×5 matrix using nested for loop.

Note:
3×5 matrix means, a Matrix with 3 rows and 5 columns.

Related Read:
Nested For Loop In C Programming Language

Logic To Print Matrix using Nested For Loop

Outer for loop selects the rows. Inner for loop prints elements of that row. Next outer for loop selects the next row, and the inner for loop prints elements for that selected row. This continues until all the elements of the Matrix are printed.

Video Tutorial: C Program To Print Matrix using Nested For Loop


[youtube https://www.youtube.com/watch?v=lYikrWLI96g]

YouTube Link: https://www.youtube.com/watch?v=lYikrWLI96g [Watch the Video In Full Screen.]


Source Code: C Program To Print Matrix using Nested For Loop

#include<stdio.h>

int main()
{
    int row, col;

    for(row = 1; row <= 3; row++)
    {
        for(col = 1; col <= 5; col++)
        {
            printf("\t%d", col);
        }

        printf("\n");
    }

    return 0;
}

Output:

        1       2       3       4       5
        1       2       3       4       5
        1       2       3       4       5

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Ionic grid system

Today lets play with Ionic grid system – it’s built with CSS Flexible Box Layout Module standard, hence it supports all the devices which ionic supports.

Topics Covered
1. Basics of row, column
2. even spacing of column
3. explicit column sizing
4. column offset
5. column positioning
6. row positioning – Going vertical
7. responsive grid

Getting started
To get started from scratch, please visit Getting Started With IONIC APP. Get your IONIC app template ready and continue with this video tutorial.

Software Versions used for the demo
1. Node: v4.2.6
2. Cordova: 6.0.0
3. Ionic: 1.7.14
4. android: Android 6.0 (API level 23)
5. OS: Demo showed on Windows 10 Operating System.

I’ve installed ionic tabs template and am editing tab-dash.html file inside www/templates folder.


[youtube https://www.youtube.com/watch?v=IYw0n9hEqMg]

YouTube Link: https://www.youtube.com/watch?v=IYw0n9hEqMg [Watch the Video In Full Screen.]



Basics of row and column

    <span class="row">
       <div class="col">.col</div>
       <div class="col">.col</div>  
    </span>

rows are specified with class row and columns with class name col

Even spacing of columns

    <span class="row">
       <div class="col">.col</div>
       <div class="col">.col</div>  
       <div class="col">.col</div>  
       <div class="col">.col</div>  
       <div class="col">.col</div>  
    </span>

In above example all columns take up 20% of space depending on the screen width of the device. i.e., 100/5 = 20. There are 5 columns.

Explicit column spacing

    <span class="row">
       <div class="col col-50">.col-50</div>
       <div class="col">.col</div>  
       <div class="col">.col</div>  
    </span>

Here the first column takes 50% of the width and the other 2 columns share the width equally i.e., 25% each.

Column offset

    <span class="row">
       <div class="col col-offset-25 col-25">.col-25</div>
       <div class="col col-25">.col-25</div>  
       <div class="col col-25">.col-25</div>  
    </span>

Above code leaves 25% offset at the beginning, then a column of width 25% followed by 2 more columns of 25% width.

Column positioning

    <span class="row">
       <div class="col col-top">.col-top</div>
       <div class="col col-center">.col-center</div>  
       <div class="col col-bottom">.col-bottom</div>  
       <div class="col">
        1 <br />2 <br />3 <br />4
       </div>
    </span>

The first column aligns itself to the top, the second one to the center and the last one to the bottom.

Row positioning – Going vertical

    <span class="row row-center">
       <div class="col">.col</div>
       <div class="col">.col</div>  
       <div class="col">.col</div>  
       <div class="col">
        1 <br />2 <br />3 <br />4
       </div>
    </span>

row-center class makes the row align itself to the center, row-top makes it align itself to the top and row-bottom makes row to align itself to the bottom.

responsive grid

    <span class="row responsive-sm">
       <div class="col">.col</div>
       <div class="col">.col</div>  
       <div class="col">.col</div>  
    </span>

You can see its effect only on real devices. You must test it with real devices having different screen size.

responsive-sm for devices smaller than landscape.
responsive-md for devices smaller portrait tablet.
responsive-lg for devices smaller than landscape tablet.

UI
Using this simple ionic grid system we can make our applications User Interface to suit our applications needs.

Further ..
For further configuration, each class uses a Sass variable that can be changed to your liking. There’s also a responsive-grid-break mixin you can use to create your own grid classes.

SELECT Columns/Fields: MongoDB

In this video tutorial we shall see selecting of key: value in MongoDB.

In RDBMSs like MySQL, we do the same using SELECT statement.
In MongoDB, we use findOne() and find() methods.

key-value-pair-mongoDB

Documents in ‘info’ collection

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> db.info.find().forEach(printjson)
{
        "_id" : ObjectId("517e829d005b19f1f0d96b25"),
        "name" : "Apple",
        "product" : "iPhone5S",
        "emp_no" : "100"
}
{
        "_id" : ObjectId("517e8377005b19f1f0d96b26"),
        "name" : "Technotip",
        "product" : "Video Tutorials - Educational",
        "emp" : [
                "Satish",
                "Kiran"
        ],
        "videos" : {
                "mongo" : "MongoDB Videos",
                "php" : "PHP Video Tutorials"
        }
}

Learn Create and Insert Documents: MongoDB.

Note:
find() returns cursor objects.
findOne() returns single object.

We can use findOne() method to select and retrieve only one record at a time.

findOne() Method

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> db.info.findOne({name: 'Technotip'}).product
Video Tutorials - Educational
 
> db.info.findOne({name: 'Technotip'}).videos
{ "mongo" : "MongoDB Videos", "php" : "PHP Video Tutorials" }
 
> db.info.findOne({name: 'Technotip'}).emp;
[ "Satish", "Kiran" ]

Syntax for retrieving normal {key: value} pair, sub-object {key: value} pair and array {key: value} pair is same.

Limitation
Using findOne() method, we could select and return only 1 {key: value} pair.

To select and return more than 1 {key: value} pair, we can make use of find() method, with 2 parameters.

SELECT Columns or Fields ( { KEY: VALUE } ): MongoDB


[youtube https://www.youtube.com/watch?v=u0WGmvJFFy4]

YouTube Link: https://www.youtube.com/watch?v=u0WGmvJFFy4 [Watch the Video In Full Screen.]



find() Method, with two parameters

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> db.info.find({name: 'Apple'}, {product: 1}).forEach(printjson);
{ "_id" : ObjectId("517e829d005b19f1f0d96b25"), "product" : "iPhone5S" }

First parameter is the condition, second parameter specifies the {key: value} pairs.

We can pass more than 1 key in second parameter; that would returns multiple {key: value} pairs.

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> db.info.find({name: 'Apple'}, {product: 1, emp_no: 1}).forEach(printjson);
{
        "_id" : ObjectId("517e829d005b19f1f0d96b25"),
        "product" : "iPhone5S",
        "emp_no" : "100"
}

1 or true means, those {key: value} pairs need to be returned.
0 or false means, excluding those {key: value} pairs, all other {key: value} pairs(records) needs to be returned.

true(0)

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> db.info.find({name: 'Apple'}, {product: true}).forEach(printjson);
{ "_id" : ObjectId("517e829d005b19f1f0d96b25"), "product" : "iPhone5S" }
> db.info.find({name: 'Apple'}, {product: true, emp_no: true}).forEach(printjson);
{
        "_id" : ObjectId("517e829d005b19f1f0d96b25"),
        "product" : "iPhone5S",
        "emp_no" : "100"
}

False(0): Exclusion

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> db.info.find({name: 'Apple'}, {product: 0, emp_no: 0}).forEach(printjson);
{ "_id" : ObjectId("517e829d005b19f1f0d96b25"), "name" : "Apple" }

Note:
True and False combination doesn’t work

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> db.info.find({name: 'Apple'}, {product: true, emp_no: false}).forEach(printjson);
Wed May 08 12:11:30.184 JavaScript execution failed: error: {
        "$err" : "You cannot currently mix including and excluding fields. 
                  Contact us if this is an issue.",
        "code" : 10053
} at src/mongo/shell/query.js:L128
> db.info.find({name: 'Apple'}, {product: 0, emp_no: 1}).forEach(printjson);
Wed May 08 12:11:40.840 JavaScript execution failed: error: {
        "$err" : "You cannot currently mix including and excluding fields. 
                  Contact us if this is an issue.",
        "code" : 10053
} at src/mongo/shell/query.js:L128

We can not combine true(1) and false(0) together in the second parameter.

Special Provision!
But we can do it with _id(ObjectId)

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> db.info.find({name: 'Apple'}, 
               {product: 1, emp_no: 1, _id: 0}).forEach(printjson);
{ "product" : "iPhone5S", "emp_no" : "100" }

Operation of second document/record in ‘info’ collection.
This illustrates that the syntax for sub-objects, array and the normal key/value pair is same.

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> db.info.find({name: 'Technotip'}, {product: 1}).forEach(printjson);
{
        "_id" : ObjectId("517e8377005b19f1f0d96b26"),
        "product" : "Video Tutorials - Educational"
}
{ "_id" : ObjectId("518363e2d73694e289255486") }
> db.info.find({name: 'Technotip'}, {product: 1, videos: 1}).forEach(printjson);
 
{
        "_id" : ObjectId("517e8377005b19f1f0d96b26"),
        "product" : "Video Tutorials - Educational",
        "videos" : {
                "mongo" : "MongoDB Videos",
                "php" : "PHP Video Tutorials"
        }
}
 
> db.info.find({name: 'Technotip'}, 
               {product: 1, videos: 1, emp: 1}).forEach(printjson);
{
        "_id" : ObjectId("517e8377005b19f1f0d96b26"),
        "product" : "Video Tutorials - Educational",
        "emp" : [
                "Satish",
                "Kiran"
        ],
        "videos" : {
                "mongo" : "MongoDB Videos",
                "php" : "PHP Video Tutorials"
        }
}
 
> db.info.find({name: 'Technotip'}, 
               {product: 1, videos: 1, emp: 1, _id: 0}).forEach(printjson);
{
        "product" : "Video Tutorials - Educational",
        "emp" : [
                "Satish",
                "Kiran"
        ],
        "videos" : {
                "mongo" : "MongoDB Videos",
                "php" : "PHP Video Tutorials"
        }
}

Note:
Two documents with same name

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{
        "_id" : ObjectId("517e8377005b19f1f0d96b26"),
        "name" : "Technotip",
        "product" : "Video Tutorials - Educational",
        "emp" : [
                "Satish",
                "Kiran"
        ],
        "videos" : {
                "mongo" : "MongoDB Videos",
                "php" : "PHP Video Tutorials"
        }
}
{ "_id" : ObjectId("518363e2d73694e289255486"), "name" : "Technotip" }
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> db.info.findOne({name: 'Technotip'})._id;
ObjectId("517e8377005b19f1f0d96b26")

If we use findOne() method on this collection, and the condition being the name key, then the oldest document will be returned.
Only one key: value pair is returned, as findOne() returns only single object.