chapter 8 exercises

Author: ivanbrennan

Diff for: ex.8.10.c

@@ -0,0 +1,53 @@
+#include <stdio.h>
+#include <stdbool.h>
+
+float absoluteValue (float n)
+{
+	if ( n < 0 )
+		n = -n;
+
+	return n;
+}
+
+float squareRoot (float n)
+{
+	float guess = 1.0;
+	float epsilon = .0001;
+
+	while ( absoluteValue ((guess * guess / n) - 1) > epsilon )
+		guess = (guess + n / guess) / 2.0;
+
+	return guess;
+}
+
+int prime (n)
+{
+	if ( n == 2 ) {
+		return 1;
+	} else if ( n > 2 ) {
+		bool isPrime = true;
+		int i;
+
+		for ( i = 2; i <= squareRoot ((float) n); i += (i > 2) ? 2 : 1 )
+			if ( n % i == 0 )
+				return 0;
+
+		return 1;
+	} else {
+		return 0;
+	}
+}
+
+int main (void)
+{
+	int n;
+	printf ("Which number do you want to check for prime? ");
+	scanf  ("%i", &n);
+
+	if ( prime (n) )
+		printf ("%i is prime\n", n);
+	else
+		printf ("%i is not prime\n", n);
+
+	return 0;
+}

Diff for: ex.8.11.c

@@ -0,0 +1,30 @@
+// sum the elements in an array of integers
+#include <stdio.h>
+
+int arraySum (int array[], int length)
+{
+	int i, sum = 0;
+
+	for ( i = 0; i < length; ++i )
+		sum += array[i];
+
+	return sum;
+}
+
+int main (void)
+{
+	int i, length = 8;
+	int array[length];
+
+	for ( i = 0; i < length; ++i )
+		array[i] = i;
+
+	printf ("The array:\n");
+	for ( i = 0; i < length - 1; ++i )
+		printf ("%i, ", array[i]);
+	printf ("%i\n", array[length - 1]);
+
+	printf ("sums to %i\n", arraySum (array, length));
+
+	return 0;
+}

Diff for: ex.8.12A.c

@@ -0,0 +1,40 @@
+#include <stdio.h>
+
+void transposeMatrix (int matrix1[4][5], int matrix2[5][4])
+{
+	int i, j;
+
+	for ( i = 0; i < 4; ++i )
+		for ( j = 0; j < 5; ++j )
+			matrix2[j][i] = matrix1[i][j];
+}
+
+int main (void)
+{
+	int i, j;
+	int matrix1[4][5] = {
+		{ 11, 12, 13, 14, 15 },
+		{ 21, 22, 23, 24, 25 },
+		{ 31, 32, 33, 34, 35 },
+		{ 41, 42, 43, 44, 45 },
+	};
+	int matrix2[5][4] = { 0 };
+
+	printf ("matrix1:\n");
+	for ( i = 0; i < 4; ++i ) {
+		for ( j = 0; j < 5; ++j )
+			printf ("%3i", matrix1[i][j]);
+		printf ("\n");
+	}
+
+	transposeMatrix (matrix1, matrix2);
+
+	printf ("...transposed to matrix2:\n");
+	for ( i = 0; i < 5; ++i ) {
+		for ( j = 0; j < 4; ++j )
+			printf ("%3i", matrix2[i][j]);
+		printf ("\n");
+	}
+
+	return 0;
+}

Diff for: ex.8.12B.c

@@ -0,0 +1,41 @@
+#include <stdio.h>
+
+void transposeMatrix (int nRows, int nCols,
+					  int matrix1[nRows][nCols], int matrix2[nCols][nRows])
+{
+	int i, j;
+
+	for ( i = 0; i < nRows; ++i )
+		for ( j = 0; j < nCols; ++j )
+			matrix2[j][i] = matrix1[i][j];
+}
+
+int main (void)
+{
+	int i, j;
+	int matrix1[4][5] = {
+		{ 11, 12, 13, 14, 15 },
+		{ 21, 22, 23, 24, 25 },
+		{ 31, 32, 33, 34, 35 },
+		{ 41, 42, 43, 44, 45 },
+	};
+	int matrix2[5][4] = { 0 };
+
+	printf ("matrix1:\n");
+	for ( i = 0; i < 4; ++i ) {
+		for ( j = 0; j < 5; ++j )
+			printf ("%3i", matrix1[i][j]);
+		printf ("\n");
+	}
+
+	transposeMatrix (4, 5, matrix1, matrix2);
+
+	printf ("...transposed to matrix2:\n");
+	for ( i = 0; i < 5; ++i ) {
+		for ( j = 0; j < 4; ++j )
+			printf ("%3i", matrix2[i][j]);
+		printf ("\n");
+	}
+
+	return 0;
+}

Diff for: ex.8.13.c

@@ -0,0 +1,42 @@
+// Program to sort an array of integers into ascending order
+
+#include <stdio.h>
+
+void sort (int a[], int n, int ascending)
+{
+	int i, j, temp;
+
+	for ( i = 0; i < n - 1; ++i )
+		for ( j = i + 1; j < n; ++j )
+			if ( (ascending && a[i] > a[j]) || (!ascending && a[i] < a[j]) ) {
+				temp = a[i];
+				a[i] = a[j];
+				a[j] = temp;
+			}
+}
+
+int main (void)
+{
+	int		i;
+	int		array[16] = { 34, -5, 6, 0, 12, 100, 56, 22,
+						  44, -3, -9, 12, 17, 22, 6, 11 };
+	void	sort (int a[], int n, int ascending);
+
+	printf ("The array before the sort:\n");
+
+	for ( i = 0; i < 16; ++i )
+		printf ("%i ", array[i]);
+
+	sort (array, 16, 1);
+	printf ("\n\nThe array after the ascending sort:\n");
+	for ( i = 0; i < 16; ++i )
+		printf ("%i ", array[i]);
+
+	sort (array, 16, 0);
+	printf ("\n\nThe array after the descending sort:\n");
+	for ( i = 0; i < 16; ++i )
+		printf ("%i ", array[i]);
+	printf ("\n");
+
+	return 0;
+}

Diff for: ex.8.14A.c

@@ -0,0 +1,56 @@
+#include <stdio.h>
+#include <stdbool.h>
+
+int n;
+float guess = 1.0;
+
+float absoluteValue (void)
+{
+	float value = (guess * guess / (float) n) - 1.0;
+
+	if ( value < 0 )
+		value = -value;
+
+	return value;
+}
+
+float squareRoot (void)
+{
+	float epsilon = .0001;
+
+	while ( absoluteValue () > epsilon )
+		guess = (guess + (float) n / guess) / 2.0;
+
+	return guess;
+}
+
+int prime (void)
+{
+	if ( n == 2 ) {
+		return 1;
+	} else if ( n > 2 ) {
+		bool isPrime = true;
+		int i;
+
+		for ( i = 2; i <= squareRoot (); i += (i > 2) ? 2 : 1 )
+			if ( n % i == 0 )
+				return 0;
+
+		return 1;
+	} else {
+		return 0;
+	}
+}
+
+int main (void)
+{
+	printf ("Which number do you want to check for prime? ");
+	scanf  ("%i", &n);
+
+	if ( prime () )
+		printf ("%i is prime\n", n);
+	else
+		printf ("%i is not prime\n", n);
+
+	return 0;
+}

Diff for: ex.8.14B.c

@@ -0,0 +1,33 @@
+// sum the elements in an array of integers
+#include <stdio.h>
+
+#define length	8
+
+int array[length];
+
+int arraySum (void)
+{
+	int i, sum = 0;
+
+	for ( i = 0; i < length; ++i )
+		sum += array[i];
+
+	return sum;
+}
+
+int main (void)
+{
+	int i;
+
+	for ( i = 0; i < length; ++i )
+		array[i] = i;
+
+	printf ("The array:\n");
+	for ( i = 0; i < length - 1; ++i )
+		printf ("%i, ", array[i]);
+	printf ("%i\n", array[length - 1]);
+
+	printf ("sums to %i\n", arraySum ());
+
+	return 0;
+}

Diff for: ex.8.14C.c

@@ -0,0 +1,41 @@
+#include <stdio.h>
+
+int matrix1[4][5] = {
+	{ 11, 12, 13, 14, 15 },
+	{ 21, 22, 23, 24, 25 },
+	{ 31, 32, 33, 34, 35 },
+	{ 41, 42, 43, 44, 45 },
+};
+int matrix2[5][4] = { 0 };
+
+void transposeMatrix (void)
+{
+	int i, j;
+
+	for ( i = 0; i < 4; ++i )
+		for ( j = 0; j < 5; ++j )
+			matrix2[j][i] = matrix1[i][j];
+}
+
+int main (void)
+{
+	int i, j;
+
+	printf ("matrix1:\n");
+	for ( i = 0; i < 4; ++i ) {
+		for ( j = 0; j < 5; ++j )
+			printf ("%3i", matrix1[i][j]);
+		printf ("\n");
+	}
+
+	transposeMatrix ();
+
+	printf ("...transposed to matrix2:\n");
+	for ( i = 0; i < 5; ++i ) {
+		for ( j = 0; j < 4; ++j )
+			printf ("%3i", matrix2[i][j]);
+		printf ("\n");
+	}
+
+	return 0;
+}

Diff for: ex.8.14D.c

@@ -0,0 +1,44 @@
+#include <stdio.h>
+
+#define nRows	4
+#define nCols	5
+
+int matrix1[nRows][nCols] = {
+	{ 11, 12, 13, 14, 15 },
+	{ 21, 22, 23, 24, 25 },
+	{ 31, 32, 33, 34, 35 },
+	{ 41, 42, 43, 44, 45 },
+};
+int matrix2[nCols][nRows] = { 0 };
+
+void transposeMatrix (void)
+{
+	int i, j;
+
+	for ( i = 0; i < nRows; ++i )
+		for ( j = 0; j < nCols; ++j )
+			matrix2[j][i] = matrix1[i][j];
+}
+
+int main (void)
+{
+	int i, j;
+
+	printf ("matrix1:\n");
+	for ( i = 0; i < 4; ++i ) {
+		for ( j = 0; j < 5; ++j )
+			printf ("%3i", matrix1[i][j]);
+		printf ("\n");
+	}
+
+	transposeMatrix ();
+
+	printf ("...transposed to matrix2:\n");
+	for ( i = 0; i < 5; ++i ) {
+		for ( j = 0; j < 4; ++j )
+			printf ("%3i", matrix2[i][j]);
+		printf ("\n");
+	}
+
+	return 0;
+}