words-problems.c

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

int main() {
    int n;
    // Take the input for n, number of strings
    scanf("%d", &n);
    char strings_given[50][100];
    for(int i = 0; i < n; i++) {
        //Read the input string from the user
        scanf("%s", strings_given[i]);
    }
    //For each character from a to z check if it is present in all the strings
    for(char c = 'a'; c <= 'z'; c++) {
        int count = 0;
        for(int i = 0; i < n; i++) {
            for(int j = 0; j < strlen(strings_given[i]); j++) {
                if(tolower(strings_given[i][j]) == c) {
                    count++;
                    break;
                }
            }
        }
        if(count == n) {
            printf("%c", c);
        }
    }
    printf("\n");
    return 0;
}