PASS Week 11/17

Problem #1:

Create a program that takes a string as input when the program is started and prints
the words of the sentence in reverse. You will need to use argc and argv in the main
function. You should not need to declare your own array but use the argv array and
a loop to present the input strings in the reverse order.
Note: Recall that char* argv[] is an array of character pointers. So each input string
occupies a row in the array.









Problem #2:

Compose a program that prompts the user to enter in 10 numbers and store them
into an array of strings one at a time. The array should be a 2d array of characters
that can hold 10 strings up to a length of 20 characters each. Handle the numerical
input as strings and store them into the array (You don’t need to reference the 2nd
dimension). Use a loop to print out the strings to verify you have your numbers
stored as asci characters. Now loop through the array and use the atof() function to
convert the string version of the numbers into a double type and add it to a sum
variable. Print out the sum and end the program. Note: scanf() will read in strings
from standard in until they encounter (a space, end of file, or newline/carriage
return) gets and fgets will include those items, which makes scanf a better choice
here

SAMPLE OUTPUT:

Enter in a number: 1
Enter in a number: 2
Enter in a number: 3
Enter in a number: 4
Enter in a number: 5
Enter in a number: 6
Enter in a number: 7
Enter in a number: 8
Enter in a number: 9
Enter in a number: 10
 1
 2
 3
 4
 5
 6
 7
 8
 9
 10
Sum: 55.00





/*** SKELETON CODE ***/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(void)
{
	char ary[10][20];
	double sum = 0.0;
	int i; //For the loops

	[YOUR CODE HERE]

	printf("Sum: %.2lf\n", sum);
	return 0;
}//end main















Problem #3:

Create a program that prompts the user for the name of a text file (example:
input.txt). Your program should verify if the file exists and report to the user if it does
or if it does not.





















Problem #4:

Analyze the following program. Figure what it is doing, and what each of its functions
and if-else conditionals do. ONLY RUN THIS PROGRAM AFTER YOU HAVE FIGURED OUT ITS FUNCTION.

#include <stdio.h>
#include <string.h>
#include <stdbool.h>

void FlushInput(void);
bool FileExists(char*);
bool CreateFile(char*, char*);

int main(void){
    FILE* fIn = NULL;
    char textIn[300];
    char fileName[80];
    char saveFile = 'y';
    bool result = false;

    printf("Enter in some text to save:");

    if(fgets(textIn,300,stdin)){
        printf("Your entered in %d characters.\n", (int) strlen(textIn));
        printf("Enter in the name of a text file: ");
        fscanf(stdin,"%s",fileName);

            if(FileExists(fileName) == true){
                printf("The file exists, enter 'y' to overwrite:");
                FlushInput();
                scanf("%c", &saveFile);

                if(saveFile == 'y')
                    result = CreateFile(textIn, fileName);
                else
                    printf("You chose not to save the data.\n");
            }
            else{
                result = CreateFile(textIn, fileName);
            }//end if-else
    }
    else {
        printf("You did not enter in anything to save.\n");
    }

    if(result)
        printf("You successfully created a file named %s\n", fileName);
    else
        printf("You did not create a file named %s\n", fileName);

    return 0;
}//end main


bool FileExists(char* fileName){
    FILE* fIn = fopen(fileName,"r");

    if(fIn == NULL)
	 	return false;
    else{
        fclose(fIn);
        return true;
    }
}//end function


void FlushInput(void){
    while(getchar() != '\n');
    return;
}//end function


bool CreateFile(char* textIn, char* fName){
    FILE* fPtr = fopen(fName,"w");

    if(fPtr == NULL){
        printf("Error opening file.\n");
        return false;
    }

    else{
        fputs(textIn, fPtr);
        fclose(fPtr);
        return true;
    }//end if-else

}//end function