This program stores a sentence entered by the user in a file.

#include <stdio.h>
#include <stdlib.h>

int main(){
    char sentence[1000];

    // creating file pointer to work with files
    FILE *fptr;

    // opening file in writing mode
    fptr = fopen("program.txt", "w");

    // exiting program 
    if (fptr == NULL) {
        printf("Error!");
        exit(1);
    }
    printf("Enter a sentence:n");
    fgets(sentence, sizeof(sentence), stdin);
    fprintf(fptr, "%s", sentence);
    fclose(fptr);
    return 0;
}

Output

Enter a sentence: C Programming is fun

Here, a file named program.txt is created. The file will contain C programming is fun text.

In the program, the sentence entered by the user is stored in the sentence variable.

Then, a file named program.txt is opened in writing mode. If the file does not exist, it will be created.

Finally, the string entered by the user will be written to this file using the fprintf() function and the file is closed.