#include <stdio.h>
 
int main() {
    FILE *fp;
    char data[200];
 
    // Step 1: Open file in append mode
    fp = fopen("output.txt", "a");
 
    // Step 2: Check if file is opened successfully
    if (fp == NULL) {
        printf("Error! Unable to open file.\n");
        return 1;
    }
 
    // Step 3: Get text from user to append
    printf("Enter text to append to the file:\n");
    fgets(data, sizeof(data), stdin);
 
    // Step 4: Write the text to the file
    fputs(data, fp);
 
    // Step 5: Close the file
    fclose(fp);
 
    printf("Data successfully appended to file.\n");
 
    return 0;
}