#include <stdio.h>
#include <string.h>
const char *keypad[] ={
    " ",
    " ",
    "ABC",
    "DEF",
    "GHI",
    "JKL",
    "MNO",
    "PQRS",
    "TUV",
    "WXYZ",
};
void generateCombinations(char * digit, int cur, char * output, int n)
{
    if (cur ==n)
    {
        output [cur] = ' ';
        printf("%s",output);
        return;
    }
    int digit = digits[cur] -'0';
    for(int i=0; keypad[digit][i] !=''; i++)
    {
        output[cur] =keypad [dogit] [i];
        generatecombinations(digits, cur +1,output ,n);
    }
}

int main()
{
    char digits[100];
    printf("Enter digits:");
    scanf("%s",digits);
    
    int n=strlan(digits);
    char output [n +1];
    generateCombinations(digits,0,output, n);
    return 0;
}