Code
/*
* -----------------------------------------------------------
* Logic Building with Computer Programming (CSU1128P)
* Instructor: Abdullahi Adem | Author: Divya Mohan
*
* This code is a part of the educational initiative by dmj.one
* with aim of empowering and inspiring learners in the field of
* Computer Science and Engineering through the respective courses.
*
* (c) 2022, Divya Mohan for dmj.one. All rights reserved.
* -----------------------------------------------------------
*/
#include <stdio.h>
#include <ctype.h>
int main()
{
printf("\n\n-- This program takes input of a sentence, writes it in the file, converts it in both lower and upper case and write them both to the file again. --\n\n");
FILE *f; // file pointer
// open the file in write mode
f = fopen("file.txt", "a");
if (f == NULL)
{
printf("Error opening file!\n");
return 1;
}
char s[100]; // array to store the user's input
printf("Enter a string: ");
fgets(s, sizeof(s), stdin); // read the string from the user using fgets
printf("Original: %s", s); // print the original string to the screen
fprintf(f, "Original: %s", s); // write the original string to the file
// write the converted strings to the file and print them to the screen
printf("Upper-case: ");
fprintf(f, "Upper-case: ");
for (int i = 0; s[i] != '\0'; i++)
{
printf("%c", toupper(s[i])); // print the upper-case character to the screen
fputc(toupper(s[i]), f); // write the upper-case character to the file
}
printf("\n");
fprintf(f, "\n");
printf("Lower-case: ");
fprintf(f, "Lower-case: ");
for (int i = 0; s[i] != '\0'; i++)
{
printf("%c", tolower(s[i])); // print the lower-case character to the screen
fputc(tolower(s[i]), f); // write the lower-case character to the file
}
printf("\n");
fprintf(f, "\n");
// close the file
fclose(f);
return 0;
}
Output
-- This program takes input of a sentence, writes it in the file, converts it in both lower and upper case and write them both to the file again. --
Enter a string: This is a demo string.
Original: This is a demo string.
Upper-case: THIS IS A DEMO STRING.
Lower-case: this is a demo string.