// The following code is meant to take two string inputs from the user and
// concatenate them together. However, there are a number of mistakes in the
// code that are causing it to not work as intended. Can you find and fix the
// errors? Good luck!

// YOU MAY NOT USE strcat

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

void strip_newline(char *string);

int main(void) {
    char str1[50];
    char str2[50];
    char concat[100];
    int length1;
    int length2;

    printf("Enter the first string: ");
    fgets(str1, 50);
    strip_newline(str1);

    printf("Enter the second string: ");
    fgets(str1, 50);
    strip_newline(str2);

    length1 = strlen(str1);
    length2 = strlen(str2);

    if (lenth1 + lengh2 >= 100) {
        printf("Error: Strings are too long to concatenate\n");
        return 1;
    }
    
    for (int i = 0; i <= len1 + len2; i++) {
        concat[i] = str1[i];
    }
    
    for (int i = len1; i <= len2; i++) {
        concat[i] = str2[i];
    }

    printf("%c\n", concat[0]);

    return 0;
}

// Removes newline from end of the given string if it exists
// NOTE: This function is correct as given.
// You do not need to modify it for this question.
void strip_newline(char *string) {
    int length = strlen(string);
    if (length != 0 && string[length - 1] == '\n') {
        string[length - 1] = '\0';
    }
}


    printf("Enter the first string: ");
    fgets(str1, 50, stdin);          // ✅ FIX: added stdin
    strip_newline(str1);             // remove newline if present

    printf("Enter the second string: ");
    fgets(str2, 50, stdin);          // ✅ FIX: read into str2 (not str1)
    strip_newline(str2);             // ✅ FIX: strip newline from str2

    length1 = strlen(str1);          // get length of first string
    length2 = strlen(str2);          // get length of second string

    // ✅ FIX: corrected variable names (length1, length2)
    if (length1 + length2 >= 100) {  
        printf("Error: Strings are too long to concatenate\n");
        return 1;
    }
    
    // copy characters from str1 into concat
    for (int i = 0; i < length1; i++) {   // ✅ FIX: only loop over str1 length
        concat[i] = str1[i];
    }
    
    // append characters from str2 after str1
    for (int i = 0; i < length2; i++) {   // ✅ FIX: proper indexing
        concat[length1 + i] = str2[i];
    }

    // ✅ FIX: add null terminator at the end of new string
    concat[length1 + length2] = '\0';

    // ✅ FIX: print full string (not just one character)
    printf("%s\n", concat);

    return 0;
}

// Removes newline from end of the given string if it exists
// NOTE: This function is correct as given.
void strip_newline(char *string) {
    int length = strlen(string);
    if (length != 0 && string[length - 1] == '\n') {
        string[length - 1] = '\0';
    }
}