อยากให้มันเลือกสินค้าแล้วเอาราคามาบวกกันได้อะครับ

#include<stdio.h>
#include<conio.h>
#include<ctype.h>
void main(void)
{
    char ans;
    do{
    clrscr();
    gotoxy(1,1);
    textcolor(14);
    textbackground(8);
    cprintf("Computer Hardware Stores\n");
    gotoxy(1,3);
    textcolor(12);
    textbackground(8);
    cprintf("Please Select 1-7\n");
    gotoxy(1,4);
    textcolor(9);
    textbackground(8);
    cprintf("1.Computer\n");
    gotoxy(1,5);
    textcolor(9);
    textbackground(8);
    cprintf("2.CPU\n");
    gotoxy(1,6);
    textcolor(9);
    textbackground(8);
    cprintf("3.Mainboard\n");
    gotoxy(1,7);
    textcolor(9);
    textbackground(8);
    cprintf("4.Monitor\n");
    gotoxy(1,8);
    textcolor(9);
    textbackground(8);
    cprintf("5.Printer\n");
    gotoxy(1,9);
    textcolor(9);
    textbackground(8);
    cprintf("6.Flash Drive\n");
    gotoxy(1,10);
    textcolor(9);
    textbackground(8);
    cprintf("7.Gaming Gear\n");
    gotoxy(1,11);
    textcolor(9);
    textbackground(8);
    cprintf(" Select : ");
    ans=getche();
    printf("\n");
    switch(ans){
        case'1': clrscr();
             printf("Computer\n\n");
             printf("1. DESKTOP PC ACER ASPIRE TC-710-644G1T00MGI/T003\n");
             printf("CPU-INTEL CORE I5-6400 RAM : 4 GB\n");
             printf("HDD : 1 TB VGA : GT 730 OS : DOS                 18,900 THB\n\n");
             printf("2. DESKTOP PC ACER ASPIRE TC-710-644G1T00MI/T008\n");
             printf("CPU : INTEL CORE I5-6400 RAM : 4 GB\n");
             printf("HDD : 1 TB VGA : INTEL HD GRAPHICS OS : DOS      15,990 THB\n\n");
             printf("3. DESKTOP PC ACER ASPIRE TC704-314G5000MI\n");
             printf("CPU : INTEL CELERON N3150 RAM : 4 GB\n");
             printf("HDD : 500 GB VGA : INTEL HD GRAPHICS OS : DOS    8,990  THB\n\n");
             printf("4. DESKTOP PC ACER ASPIRE TC704-374G1T00MI\n");
             printf("CPU : INTEL PENTIUM J3710D RAM : 4 GB\n");
             printf("HDD : 1 TB VGA : UMA OS : DOS                    10,990 THB\n\n");
             printf("5. DESKTOP PC ACER PREDATOR G3-710-648G1T00MGI\n");
             printf("CPU : INTEL CORE I5-6400 RAM : 8 GB\n");
             printf("HDD : 1 TB VGA : GTX 950 2GB OS : WINDOWS 10     38,900 THB\n");
            break;
        case'2' :clrscr();
             printf("CPU\n\n");
             printf("CPU AMD AM3+ FX-4300 3.8 GHz\n");
             printf("CORES : 4 THREADS : 4                   3,590  THB\n\n");
             printf("CPU AMD AM3+ FX-4350 3.6 GHz\n");
             printf("CORES : 4 THREADS : 4                   3,930  THB\n\n");
             printf("CPU AMD AM3+ FX-8370 4.0 GHz\n");
             printf("CORES : 8 THREADS : 8                 7,590  THB\n\n");
             printf("CPU AMD AM3+ FX-9370 4.4 GHz\n");
             printf("CORES : 8 THREADS : 8                   7,790  THB\n\n");
            break;
        case'3' :clrscr();
             printf("Mainboard\n\n");
             printf("MAINBOARD AM3+ ASROCK 960GM-VGS3 FX\n");
             printf("SOCKET : AM3+ CHIPSET : AMD 760G / AMD SB710\n");
             printf("MEMORY : 2 x DDR3 DIMM                            1,390  THB\n\n");
             printf("MAINBOARD AM3+ ASROCK 970 EXTREME3 (REV2)\n");
             printf("SOCKET : AM3+ CHIPSET : AMD 970 / AMD SB950\n");
             printf("MEMORY : 4 x DDR3 DIMM                  2,750  THB\n\n");
             printf("MAINBOARD AM3+ MSI 990FXA GAMING\n");
             printf("SOCKET : AM3+ CHIPSET : AMD 990FX & SB950\n");
             printf("MEMORY : 4 x DDR3 DIMM                            4,890  THB\n\n");
             printf("MAINBOARD AM3+ GIGABYTE 990FX GAMING\n");
             printf("SOCKET : AM3+ CHIPSET : AMD 990F/ SB950\n");
             printf("MEMORY : 4 x DDR3 DIMM                 5,190     THB\n\n");
            break;
        case'4' :clrscr();
             printf("Monitor\n\n");
             printf("18.5"" LED SAMSUNG LS19F350HNEXXT\n");
             printf("SIZE : 18.5"" CONTRAST : MEGA RESPONSE\n");
             printf("TIME : 14 ms                      2,790   THB\n\n");
             printf("24"" LED SAMSUNG LS24F350FHEXXT\n");
             printf("SIZE : 24"" CONTRAST : 1000 : 1 RESPONSE\n");
             printf("TIME : 4 (GTG)                      4,690   THB\n\n");
             printf("MONITOR 27 SAMSUNG LC27F390FHEXXT\n");
             printf("SIZE : 27"" CONTRAST : 3000:1 RESPONSE\n");
             printf("TIME : 4 ms                       12,900  THB\n\n");
             printf("34"" UHD SAMSUNG 34E790CNS/XT (CURVED)\n");
             printf("SIZE : 34"" CONTRAST : 3000:1 RESPONSE\n");
             printf("TIME : 4 (GTG) ms                             31,900  THB\n\n");
            break;
        case'5' :clrscr();
             printf("Printer\n\n");
             printf("PRINTER RICOH SP 211 LASER\n");
             printf("MONO LASER : PRINT                  1,990   THB\n\n");
             printf("PRINTER RICOH SP C240DN LASER COLOR\n");
             printf("COLOR LASER : PRINT                  4,690      THB\n\n");
             printf("PRINTER RICOH SP C250DN LASER COLOR\n");
             printf("COLOR LASER : PRINT/WIFI               5,990   THB\n\n");
             printf("PRINTER RICOH SP C250SF LASER COLOR ALL IN ONE\n");
             printf("COLOR INKJET : PRINT/SCAN/COPY/FAX/WIFI              15,990  THB\n\n");
            break;
        case'6' :clrscr();
             printf("Flash Drive\n\n");
             printf("8 GB FLASH DRIVE KINGSTON SE9 (DTSE9H/8GB)\n");
             printf("CAPACITY : 8 GB \n");
             printf("READ SPEED : 10 MB/s WRITE SPEED : 5 MB/s            130     THB\n\n");
             printf("16 GB FLASH DRIVE KINGSTON (DTDUO3C/16GB)\n");
             printf("CAPACITY : 16 GB \n");
             printf("SPEED : 100 MB/s WRITE READ SPEED : 15 MB/s          330    THB\n\n");
             printf("32 GB FLASH DRIVE KINGSTON (DTDUO3C/32GB)\n");
             printf("CAPACITY : 32 GB READ SPEED : 100 MB/s\n");
             printf("WRITE SPEED : 15 MB/s                               450    THB\n\n");
             printf("64 GB FLASH DRIVE KINGSTON (DTIG4/64GBFR) USB 3.1\n");
             printf("CAPACITY : 64 GB READ SPEED : N/A WRITE SPEED : N/A      560     THB\n\n");
            break;
        case'7' :clrscr();
             printf("Gaming Gear\n\n\n");
             printf("Keyborad\n\n");
             printf("KEYBOARD ASUS CERBERUS\n");
             printf("FEATURES : RUBBER DOME                      1,290  THB\n\n");
             printf("KEYBOARD ASUS CERBERUS WHITE\n");
             printf("FEATURES : MEMBRANE WITH RUBBER DOME              1,690     THB\n\n");
             printf("Mouse\n\n\n");
             printf("MOUSE ASUS CERBERUS\n");
             printf("OPTICAL SENSOR : 2500");
             printf("DPI SUPPORT : PC WITH USB PORT        690  THB\n\n");
             printf("MOUSE ASUS ROG GLADIUS\n");
             printf("OPTICAL SENSOR : 6400\n");
             printf("DPI SUPPORT : PC WITH USB PORT                  1,990     THB\n\n");
            break;
        default:printf("Please select 1-7\n");
    }
    printf("\n");
    do{
        printf("Do you want to continue?(N/E)");
        ans=getche();
        printf("\n");
    }while(toupper(ans) !='N'&&toupper(ans)!='E');
    }while(toupper(ans)=='N');
       getch();
}