Pulsa Captcha (fork & pipe)

/*
SOAL
=========================================================================================================================
Input :
No Handphone [10-12], depan harus 08, kalo ketik exit dia keluar
Pilih provider [XL || Telkomsel || Indosat] case TIDAK sensitif
pilih pulsa [10000 || 25000 || 50000 || 100000]
Masukan CAPTCHA (*) case sensitive

Output:
Detail pemesanan
==================
No HP : no hp dengan sensor 3 no terkahir
Provider : pilihan provider//sudah di HURUF BESARKAN SEMUA
Pulsa : Rp. pilihan pulsa,00
No transaksi : [2 kata pertama merk Provider]+[3 digit no hp terakhir]+[2 kata pertama dari CAPTCHA di huruf kecilkan]

//format captca adalah random 2 huruf+no terakhir di no hp+2kata pertama provider HURUF BESAR

Contoh accepted input :
No HP : 087840094200
Provider : telKomsEL
Pulsa : 50000
Captcha (GF200XL) : GF200TE

Output :
No HP : 087840094***
Provider : TELKOMSEL
Pulsa : Rp. 50000,00
No Transaksi : TE200gf

PENJELASAN :
input ->captcha, GF dari random 2 huruf, 200 dari 3 no belakang hp, XL kode provider
output -> no hp di sensor 3 paling belakang
provider di huruf besarkan semuanya
pulsa ditambahkan Rp. ,00
No transaksi, TE dari telkomsel, 200 3 no belakang, gf randomnya dikecilin hurufnya

*hint, ASCII A-Z itu 65-92;


*/
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <stdlib.h>

struct data {
    char no[15];
    char provider[10];
    int pulsa;
    char captcha[10];
};

int main(){
    struct data cust;
    pid_t pFork;
    int pipes[2],i,j,flag;
    char cpt[10];
    if(pipe(pipes)<0){
        printf("Error Pipe");
        exit(1);
    }
    int r1,r2;
    pFork=fork();
    if(pFork==0){
        printf("\nChild Process\n=========================\n\n");
        do{
            flag=0;
            printf("No Handphone [10...12][08xxxxxx][exit to close]: ");
            scanf("%s",cust.no);getchar();
            if(strlen(cust.no)<10||strlen(cust.no)>12)
                flag=1;
            if(cust.no[0]!='0'||cust.no[1]!='8')
                flag=1;
            for(j=0;j<strlen(cust.no);j++){
                if(!isdigit(cust.no[j]))
                    flag=1;
            }
            if(strcasecmp(cust.no,"exit")==0){
                printf("Program is Quiting\n");
                exit(1);
            }
        }while(flag==1);
        do{
            flag=0;
            printf("Pilih Provide [XL || Telkomsel || Indosat]: ");
            scanf("%s",cust.provider);getchar();
            if(strcasecmp(cust.provider,"xl")!=0&&strcasecmp(cust.provider,"telkomsel")!=0&&strcasecmp(cust.provider,"indosat"))
                flag=1;
        }while(flag==1);
        do{
            flag=0;
            printf("Pilih Pulsa [10000 || 25000 || 50000 || 100000]: ");
            scanf("%d",&cust.pulsa);getchar();fflush(stdin);
            if(cust.pulsa!=10000&&cust.pulsa!=25000&&cust.pulsa!=50000&&cust.pulsa!=100000)
                flag=1;
        }while(flag==1);
        srand(time(NULL));
        r1=rand()%26+65;
        r2=rand()%26+65;
        cpt[0]=r1;
        cpt[1]=r2;
        cpt[2]=cust.no[strlen(cust.no)-3];
        cpt[3]=cust.no[strlen(cust.no)-2];
        cpt[4]=cust.no[strlen(cust.no)-1];
        cpt[5]=toupper(cust.provider[0]);
        cpt[6]=toupper(cust.provider[1]);
        cpt[7]='\0';
        do{
            flag=0;
            printf("Masukan Captcha (%s)[case sensitive]: ",cpt);
            scanf("%s",cust.captcha);getchar();
            if(strcmp(cust.captcha,cpt)!=0)
                flag=1;
        }while(flag==1);
        close(pipes[0]);
        write(pipes[1],(struct data*)&cust,sizeof(cust));
    }
    else if(pFork>0){
        close(pipes[1]);
        read(pipes[0],(struct data*)&cust,sizeof(cust));
        printf("\nParent Process\n=========================\n\n");
        char noTemp[10];
        strncpy(noTemp,cust.no,strlen(cust.no)-3);
        printf("No HP : %s***\n",noTemp);
        printf("Provider : ");
        for(j=0;j<strlen(cust.provider);j++)
            printf("%c",toupper(cust.provider[j]));
        printf("\nPulsa : Rp. %d,00\n",cust.pulsa);
        printf("No Transaksi : %c%c%c%c%c%c%c\n",toupper(cust.provider[0]),toupper(cust.provider[1]),
            cust.no[strlen(cust.no)-3],cust.no[strlen(cust.no)-2],cust.no[strlen(cust.no)-1],
            tolower(cust.captcha[0]),tolower(cust.captcha[1]));
    }
}