chapter 5 exercises

Author: ivanbrennan

ex.5.11.c

@@ -0,0 +1,21 @@
+// Sum the digits of a user-supplied integer
+
+#include <stdio.h>
+
+int main (void)
+{
+	int number, sum;
+
+	printf ("Enter an integer: ");
+	scanf  ("%i", &number);
+
+	printf ("The digits of %i sum to ", number);
+	sum = 0;
+	while ( number > 0 ) {
+		sum += number % 10;
+		number /= 10;
+	}
+	printf ("%i\n", sum);
+
+	return 0;
+}

ex.5.2.c

@@ -0,0 +1,15 @@
+// Program to display squares
+
+#include <stdio.h>
+
+int main (void)
+{
+	printf ("THE FIRST TEN SQUARES\n\n");
+	printf (" n       n²\n");
+	printf ("---     ---\n");
+
+	for ( int n = 1; n <= 10; ++n )
+		printf ("%2i      %3i\n", n, n * n);
+
+	return 0;
+}

ex.5.3.c

@@ -0,0 +1,15 @@
+// Program to generate every fifth triangular number from 5 to 50
+
+#include <stdio.h>
+
+int main (void)
+{
+	printf ("EVERY FIFTH TRIANGULAR NUMBER FROM 5 TO 50\n\n");
+	printf (" n       triangular number\n");
+	printf ("---      -----------------\n");
+
+	for ( int n = 5; n <= 50; n += 5 )
+		printf ("%2i        %4i\n", n, n * (n + 1) / 2);
+
+	return 0;
+}

ex.5.4.c

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+// Generate a table of the first 10 factorials
+
+#include <stdio.h>
+
+int main (void)
+{
+	printf ("FIRST 10 FACTORIALS\n\n");
+	printf (" n         n!\n");
+	printf ("---       -------\n");
+
+	for ( int n = 1; n <= 10; ++n ) {
+		int factorial = 1;
+
+		for ( int i = n; i > 1; --i)
+			factorial *= i;
+
+		printf ("%2i        %7i\n", n, factorial);
+	}
+
+	return 0;
+}

ex.5.5.c

@@ -0,0 +1,18 @@
+#include <stdio.h>
+
+int main (void)
+{
+	int n, two_to_the_n;
+
+	printf ("TABLE OF POWERS OF TWO\n\n");
+	printf (" n     2 to the n\n");
+	printf ("---    ---------------\n");
+
+	two_to_the_n = 1;
+	for ( n = 0; n <= 10; ++n ) {
+		printf ("%2i        %i\n", n, two_to_the_n);
+		two_to_the_n *= 2;
+	}
+
+	return 0;
+}

ex.5.6.c

@@ -0,0 +1,21 @@
+// Program to generate a table of triangular numbers
+
+#include <stdio.h>
+
+int main (void)
+{
+	int n, triangularNumber;
+
+	printf ("TABLE OF TRIANGULAR NUMBERS\n\n");
+	printf (" n    Sum from 1 to n\n");
+	printf ("---   ---------------\n");
+
+	triangularNumber = 0;
+
+	for ( n = 1; n <= 10; ++n ) {
+		triangularNumber += n;
+		printf ("%-2i          %i\n", n, triangularNumber);
+	}
+
+	return 0;
+}

ex.5.7.c

@@ -0,0 +1,15 @@
+#include <stdio.h>
+
+int main (void)
+{
+	int dollars, cents, count;
+
+	for ( count = 1; count <= 10; ++count ) {
+		printf ("Enter dollars: ");
+		scanf  ("%i", &dollars);
+		printf ("Enter cents: ");
+		scanf  ("%i", &cents);
+		printf ("$%i.%.2i\n\n", dollars, cents);
+	}
+	return 0;
+}

ex.5.8.c

@@ -0,0 +1,23 @@
+#include <stdio.h>
+
+int main (void)
+{
+	int n, number, triangularNumber, counter;
+
+	printf ("How many triangular numbers do you want to calculate? ");
+	scanf  ("%i", &counter);
+
+	for ( ; counter > 0; --counter ) {
+		printf ("What triangular number do you want? ");
+		scanf  ("%i", &number);
+
+		triangularNumber = 0;
+
+		for ( n = 1; n <= number; ++n )
+			triangularNumber += n;
+
+		printf ("Triangular number %i is %i\n\n", number, triangularNumber);
+	}
+
+	return 0;
+}

ex.5.9.2.c

@@ -0,0 +1,21 @@
+/* Program to calculate the 200th triangular number
+   Introduction of the for statement                 */
+
+#include <stdio.h>
+
+int main (void)
+{
+	int n, triangularNumber;
+
+	triangularNumber = 0;
+
+	n = 1;
+	while ( n <= 200 ) {
+		triangularNumber = triangularNumber + n;
+		n = n + 1;
+	}
+
+	printf ("The 200th triangular number is %i\n", triangularNumber);
+
+	return 0;
+}

ex.5.9.3.c

@@ -0,0 +1,23 @@
+// Program to generate a table of triangular numbers
+
+#include <stdio.h>
+
+int main (void)
+{
+	int n, triangularNumber;
+
+	printf ("TABLE OF TRIANGULAR NUMBERS\n\n");
+	printf (" n    Sum from 1 to n\n");
+	printf ("---   ---------------\n");
+
+	triangularNumber = 0;
+
+	n = 1;
+	while ( n <= 10 ) {
+		triangularNumber += n;
+		printf ("%2i          %i\n", n, triangularNumber);
+		++n;
+	}
+
+	return 0;
+}