โปรแกรมคำนวณน้ำประปา

#include  "stdio.h"

#include "conio.h"

void main()

{

int end=0,unit,price,total;

char choice;

do

{

clrscr();

gotoxy(20,5);printf("Calculate Papa\n");

gotoxy(20,6);printf("1. Rate\n");

gotoxy(20,7);printf("2. Calculate\n");

gotoxy(20,8);printf("3. Exit");

switch (choice=getch())

{

case '1' :

clrscr();

                        gotoxy(20,5);printf("0 -  10 unit   2 Baht/unit\n");

gotoxy(20,6);printf("11 - 20 unit  4 Baht/unit\n");

gotoxy(20,7);printf("> 20 unit      5 Baht/unit\n");

gotoxy(20,9);printf("Press any key to continue");

getch();

end = 0;

break;

case '2' :

case2: clrscr();

                gotoxy(20,5);printf("Unit : ");scanf("%d",&unit);

if (unit > 0 && unit <= 10) price = 2;

else if (unit >=11 && unit <=20) price = 4;

else if (unit > 20) price = 5;

else goto case2;

total = unit * price;

gotoxy(20,6);printf("%d Baht/unit",unit);

gotoxy(20,7);printf("Pay %3d Baht",total);

gotoxy(20,9);printf("Press any key to continue");

getch();

end = 0;

break;

case '3' :

end = 1;

break;

// default :  goto again;

}

}

while (end == 0);

}

พัฒนาโปรแกรมเพื่อทำการแสดงผลดังตัวอย่าง (File name: star.cpp)

*
**
***

****

#include "stdio.h"

#include "conio.h"

#include "string.h"

void main()

{

int count=20,i;

char star[20] = "";

clrscr();

for(i=1;i<=count;i++)  printf("%s\n", strcat (star,"*"));

}

โปรแกรมเพื่อหาผลรวมของตัวเลขคู่ และเลขคี่ ที่อยู่ระหว่าง 0 ถึง 100

#include "stdio.h"

#include "conio.h"

void main()

{

int sum1=0,sum2=0,i;

clrscr();

for(i=1;i<=100;i++) 

if (i%2==0) sum1+=i; else sum2+=i;

printf("Odd Value: 1+3+5+7+9+11+…+99=%d\n",sum2);

printf("Even Value: 2+4+6+8+10+12+…+100=%d\n",sum1);

getch();

}