/*
we ask our user to enter a valid integer
and we output the square of the integer
*/
#include <stdio.h>
#include <stdlib.h>

int main()
{
    int inputInteger; //string used to store user input
    int  inputSquared;// used to store the square of a valid integer.

    printf("Enter an Integer value....\n");
    scanf("\n%d",&inputInteger);//get input from user

    printf("You entered : %d\n", inputInteger);

    inputSquared = inputInteger*inputInteger;//find square
    printf("\n%d squared is %d\n",inputInteger, inputSquared);
    printf("\nSuccess!  Exiting program\n");

    return 0;
}

/*
this programs shows how to validate user input as integers.
if the user enters a valid integer, we output the square of the integer,
otherwise we output an error message and prompt the user to re enter  a valid integer
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h> //in order touse true and false

int main()
{
    char input[50]; //string used to store user input
    int  inputAsAnInteger;//used store the converted input  as an integer
    int  inputSquared;// used to store the square of a valid integer.

    while(true)//loop 'infinitely'
    {
        printf("Enter an Integer value....\n");
        scanf("%s",&input);//get input from user

        printf("You entered : %s\n", input);

        inputAsAnInteger=atoi(input);//convert input to integer

        if (inputAsAnInteger==0)//if the input is not a number......
        {
            printf("Invalid input entered\n\n");
        }
        else//input is a number
        {

            inputSquared = inputAsAnInteger*inputAsAnInteger;//find square
            printf("\n%d squared is %d\n",inputAsAnInteger, inputSquared);
            printf("\nSuccess!  Exiting program\n");
            break;//exit 'infinite' loop.
        }
    }
    return 0;
}

/*
this programs shows how to validate user input as integers.
if the user enters a valid integer, we output the square of the integer,
otherwise we output an error message and prompt the user to re enter  a valid integer
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h> //in order to use true and false
#include <ctype.h>   // in order to use the isdigit function.

bool isNumber(char* stringArray);

int main()
{
    char input[50]; //string used to store user input
    int  inputAsAnInteger;//used store the converted input  as an integer
    int  inputSquared;// used to store the square of a valid integer.

    while(true)//loop 'infinitely'
    {
        printf("Enter an Integer value....\n");
        scanf("%s",&input);//get input from user

        printf("You entered : %s\n", input);


        if (!isNumber(input))//if the input is not a number......
        {
            printf("Invalid input entered\n\n");
        }
        else//input is a number
        {
            inputAsAnInteger=atoi(input);//convert input to integer
            inputSquared = inputAsAnInteger*inputAsAnInteger;//find square
            printf("\n%d squared is %d\n",inputAsAnInteger, inputSquared);
            printf("\nSuccess!  Exiting program\n");
            break;//exit 'infinite' loop.
        }
    }
    return 0;
}

bool isNumber(char* stringArray)
{

    //go through each character
    //location in the array until
    //we reach the null character (end of input)
    for (int i = 0; stringArray[i]!='\000'; i++)
    {
        if(isdigit(stringArray[i])==0)//if the current character is not a digit....
            return false; //return false and end function here

    }

    return true;//return true since the entire array contained numeric characters
}