Author: Abhishek Gupta

I am Abhishek from India. I have been working as a software engineer from last 6+ years, and it is my passion to learn new things and implement them as a practice.
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AngularJS: Prevent form submission or stop page refresh on submit

I have recently started learning AngularJS and came across form that would refresh every time I click the submit button. So, here are a couple of ways to prevent that from happening.

HTML Form

<div ng-app="my-app">
  <div ng-controller="myFormController">
    <form action="test_submit.php" method="post" accept-charset="utf-8" name="myTestForm" ng-submit="myTestForm.$valid && submit()" novalidate>
      <div>
        <label for="fname">First Name</label>
        <input type="text" ng-model="dataForm.fname" name="fname" id="fname" required>
      </div>

      <div>
        <label for="lname">Last Name</label>
        <input type="text" ng-model="dataForm.lname" name="lname" id="lname" required>
      </div>

      <div>
        <label for="email">Email</label>
        <input type="text" ng-model="dataForm.email" name="email" id="email" required>
      </div>

      <div>
        <button name="submit" ng-disabled="myTestForm.$invalid" type="submit">Submit</button>
      </div>
    </form>
  </div>
</div>

Angular JS

var myApp = angular.module('my-app', []);

myApp.controller('myFormController', function($scope, $http) {
  $scope.dataForm = {};

  $scope.submit = function() {
    // Ajax
  };
});

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Gauss Elimination method in C language using Lower triangular matrix

This is a simple C language program that calculates solution of n-linear equations using Non-pivotal Gauss Elimination method. It uses lower triangular matrix to do so, for upper triangular matrix visit here.

#include<stdio.h>
#include<conio.h>
 
float matrix[10][10], m, temp[10];
int i, j, k, n;
 
void lower_traingularisation() {
    for (i=n-1; i>0; i--)
        for (j=i-1; j>=0; j--) {
            m	= matrix[j][i]/matrix[i][i];
            for (k=0; k<n+1; k++) {
                matrix[j][k]	= matrix[j][k]-(m*matrix[i][k]);
            }
        }
} //lower_traingularisation
 
void back_subsitution() {
    for (i=0; i<n; i++) {
        m	= matrix[i][n];
        for (j=0; j<i; j++)
            m	= m - temp[j] * matrix[i][j];
        temp[i]	= m/matrix[i][i];
        printf("\n x%d => %f", i+1, temp[i]);
    }
} // back_subsitution
 
void main() {
    printf("Enter number. of variables :: ");
    scanf("%d", &n);
 
    printf("Enter the augmented matrix: \n");
    for (i=0; i<n; i++)
        for (j=0; j<n+1; j++)
            scanf("%f", &matrix[i][j]);
 
    lower_traingularisation();
 
    printf("The lower traingular matrix is : \n");
 
    for (i=0; i<n; i++) {
        for (j=0; j<n+1; j++)
            printf("%f \t", matrix[i][j]);
        printf("\n");
    }
 
    printf("The required result is : \n");
 
    back_subsitution();
 
    getch();
} // main
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Gauss Elimination method for solving n-linear equations in C language

This is a simple C language program that calculates solution of n-linear equations using Non-pivotal Gauss Elimination method. It uses upper triangular matrix to do so, for solution using lower triangular matrix visit here.

#include<stdio.h>
#include<conio.h>
 
float matrix[10][10], m, temp[10];
int i, j, k, n;
 
void upper_triangularization() {
	for (i=0; i<n-1; i++)
		for (j=i+1; j<n; j++) {
			m	= matrix[j][i]/matrix[i][i];
			for (k=0; k<n+1; k++) {
				matrix[j][k]	= matrix[j][k]-(m*matrix[i][k]);
			}
		}
} //upper_traingulisation
 
void back_subsitution() {
	for (i=n-1; i>=0; i--) {
		m	= matrix[i][n];
		for (j=n-1; j>i; j--)
			m	= m - temp[n-j] * matrix[i][j];
		temp[n-i]	= m/matrix[i][i];
		printf("\n x%d => %f", i+1, temp[n-i]);
	}
} // back_subsitution
 
void main() {
	printf("Enter number. of variables :: ");
	scanf("%d", &n);
 
	printf("Enter the augmented matrix: \n");
	for (i=0; i<n; i++)
		for (j=0; j<n+1; j++)
			scanf("%f", &matrix[i][j]);
 
	upper_triangularization();
 
	printf("The upper traingular matrix is : \n");
 
	for (i=0; i<n; i++) {
		for (j=0; j<n+1; j++)
			printf("%f \t", matrix[i][j]);
		printf("\n");
	}
 
	printf("The required result is : \n");
 
	back_subsitution();
 
	getch();
} // main
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Insertion And Deletion Operation Over Multiple Queue In C language

A simple C language program to implement multiple queues in a single dimension array.
This is a revised version of Insertion And Deletion Operation Over Multiple Queue | multiple queue in data structure.

#include
#include
# define max 20

int insq (int queue[max], int qno, int rear[], int limit[], int *data) {
	if (rear[qno] == limit[qno])
		return(-1);
	else {
		rear[qno]++; //... rear[qno] = rear[qno] + 1;
		queue[ rear[qno] ] = *data;
		return(1);
	} // else
} // insq

int delq (int queue[max], int qno, int front[], int rear[], int *data) {
	if( front[qno] == rear[qno] )
		return(-1);
	else {
		front[qno]++; //... front[qno] = front[qno] + 1;
		*data = queue[ front[qno] ];
		return(1);
	} // else
} // delq

int getQueueNumber(int n) {
	int qNo=0;
	Inva:
	printf("\n Enter a Logical Queue Number (1 to %d) : ", n);
	scanf("%d", &qNo);
	if (qNo<1 || qNo >n) {
		printf(" Invalid Queue Number. Please try again.\n");
		goto Inva;
	}
	return qNo;
}

void main() {
	int queue[max],  data;
	int bott[10], limit[10], f[10], r[10];
	int i, n, qno, size, option, reply;

	printf("\n C Language program to implement the Multiple Queues \n");
	printf("\n How Many Queues ? : ");
	scanf("%d", &n);
	size = max / n; //... Get Max. size for each Queue

	//... Initialize bottom for each Queue

	bott[0] = -1; //... Bottom of first Queue is -1
	for(i = 1; i < n; i++)
		bott[i] = bott[i-1] + size;

	//... Initialize Limit of each Queue

	for(i = 0; i < n; i++) //... Limit of i'th Queue is equal to bottom of i'th Queue + Size
		limit[i] = bott[i] + size;

	//... Initialize Front & Rear of each Queue
	//... Initial value of Front & Rear of each Queue is same as its Bottom Value

	for(i = 0; i < n; i++)
		f[i] = r[i] = bott[i];

	//... Process the Queues

	do {
		printf("\n\n C Language program to implement the Multiple Queues \n");
		printf("\n 1. Insert in a Queue");
		printf("\n 2. Delete from a Queue");
		printf("\n 3. Print from a Queue");
		printf("\n 3. Exit \n");
		printf("\n Select proper option ( 1 / 2 / 3 / 4) : ");
		scanf("%d", &option);
		switch(option) {
			case 1 : //... Insert
				qno	= getQueueNumber(n);
				printf("\n Enter Data : ");
				scanf("%d", &data);
				reply = insq(queue, qno-1, r, limit, &data);
				if( reply == -1)
					printf("\n Queue %d is Full \n", qno);
				else
					printf("\n %d is inserted in a Queue No. %d \n", data, qno);
				break;
			case 2 : //... Delete
				qno	= getQueueNumber(n);
				reply = delq(queue, qno-1, f, r, &data);
				if( reply == -1)
					printf("\n Queue %d is Empty \n", qno);
				else
					printf("\n %d is deleted from Queue No. %d \n", data, qno);
				break;
			case 3:
				qno	= getQueueNumber(n);
				printf("\n Elements of Queue %d are as : ", qno);
				if (f[qno-1]==r[qno-1]) {
					printf("\n Queue is empty");
					break;
				}
				for (i=f[qno-1]+1; i<=r[qno-1]; i++)
					printf("%d\t", queue[i]);
				printf("\n");
				break;
			case 4 :
				break;
			default:
				printf("\n Invalid input. Please try again.");
		} // switch
	}while(option!=4);
} // main
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Getting started development on android with eclipse

Android Image

This post is just a quickie on how to get yourself started with Android development and the step-by-step guide about the basic tools needed to do so. Now there are many ways using which you can start development. But the simplest way is using Eclipse IDE. So, here’s a simple guide for a complete beginner.

For a complete beginner, it would be best to get eclipse and android sdk using this full-felged suite (eclipse, ADT, SDK Manager combined all together), in which case the first four steps of this tutorial can be skipped. Or download each tool separately, and continue with the steps given below.

Step 1. Download Eclipse

Although there are a lot of IDE’s that can be used to start development but eclipse is the most recommended to do so. You can download Eclipse using this link.

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