Programming - storage types, if/else, & while loops(2)

Administrivia

Practice Web Page - http://www.cs.tau.ac.il/~efif/courses/Programming_Fall_04

printf() & scanf()

A program that reads 2 integers and prints out their difference and quotion

#include <stdio.h>

int main()
{
  int num1, num2, dif, div;	

  printf("Enter two positive numbers: ");
  scanf("%d%d", &num1, &num2);
  dif = num1 - num2;
  printf("%d subtracted from %d is %d\n", num2, num1, dif);
  div = num1 / num2;
  printf("%d divided by %d is %d\n", num1, num2, div);
  return 0;
}

oper.c

modulus (or "remainder") & division

A program that prints the sum of the digits of a 2-digit number

#include <stdio.h>

int main()
{
  int sum, num;

  printf("Enter a 2-digit number: ");
  scanf("%d", &num);
  sum = num % 10;
  num = num / 10;
  sum = sum + num;
  printf("The digits sum is %d\n", sum);
  return 0;
}

digit2.c

modulus (or "remainder") & division

A program that prints the sum of the digits of a 3-digit number

#include <stdio.h>

int main()
{
  int sum, num;

  printf("Enter a 3-digit number: ");
  scanf("%d", &num);
  sum = num % 10;
  num = num / 10;
  sum = sum + num % 10;
  num = num / 10;
  sum = sum + num % 10;
  printf("The digits sum is %d\n", sum);
  return 0;
}

digit3.c

Storage types

Name	Bytes	Range	Print
float	4	3.4E +/- 38	%f
double	8	1.7E +/- 308	%lf
int	Typically 4	-2³¹ - 2³¹-1	%d
char	1	-128 - 127	%c

Casting

A program that prints the length of a Marathon in Kilometers

#include <stdio.h>

int main()
{
  int miles = 26, yards = 385;
  double kilometers;

  kilometers = 1.609 * (miles + yards / 1760.0);
  /* kilometers = 1.609 * (miles + (double)yards / 1760); */
  /* kilometers = 1.609 * (miles + yards / 1760); */
  printf("A marathon is %lf kilometers.\n", kilometers);
  return 0;
}

1760.0
- data type is double
marathon.c

if-else statement

  if (expression)
    statement₁
  else
    statement₂

nesting of if statements

you can use any statement as the body of an if

even another if statement

#include <stdio.h>

int main()
{
  int a, b;

  printf("Enter two Numbers: ");
  scanf("%d%d", &a, &b);
  if (a == b)
    printf("%d==%d\n", a, b);
  else
    if (a > b)
      printf("%d>%d\n", a, b);
    else
      printf("%d<%d\n", a, b);
  return 0;
}

val.c

while loops

while ( expression ) statement

A program that calculates the factorial of a number

#include <stdio.h>

int main()
{
  int i, n, fact = 1;

  printf("Enter a number: ");
  scanf("%d", &n);
  i = 1;
  while (i <= n) {
    fact *= i;
    i++;
  }
  printf("The factorial is %d\n", fact);
  return 0;
}

fact.c

while loops

A program that raises a to the power of b

#include <stdio.h>

int main()
{
  int a,  b, i, power;

  printf("Enter 2 numbers: ");
  scanf("%d%d", &a, &b);
	
  i = 1;
  power = 1;
  while (i <= b) {
    power = power * a;
    i++;
  }
  printf("%d to the power of %d is %d\n", a, b, power);
  return 0;
}

pow.c

while loops

A program that sums a sequence of numbers

#include <stdio.h>

int main()
{
  int num, i, counter, sum;
  printf("Enter the expected number of integers: ");
  scanf("%d", &counter);	

  i = 1;
  sum = 0;
  while (i <= counter) {
    printf("Enter a number: ");
    scanf("%d", &num);
    sum += num;
    i++;
  }
  printf("The numbers sum is %d\n", sum);
  return 0;
}

sum.c

Maintained by Efi Fogel. Last modified: November 05 2003.