Chapter 2 Algorithms - the Soul of Programs
Example 2.1 Factorial of Five

#include <stdio.h>
int main()
{
	int i = 1, j;
	for ( j = 1; j < 6; j++ )
		i = i * j;
	printf( "5!=%d\n", i );
}

The results are as follows:

Example 2.3 determines whether each year from 2000 to 2500 is a leap year and outputs the results.

#include <stdio.h>
int main()
{
	int i;
	for ( i = 2000; i <= 2500; i++ )
		if ( i % 4 = 0 && i % 100 != 0 || i % 400 = 0 )
			printf( "%d\t", i );
		else
			continue;
}
//The results are as follows:

Example 2.4 Seek 1-1/2+1/3-1/4+'''+1/99-1/100

  #include <stdio.h>
    int main()
    {
    	int	sign	= 1;
    	double	deno	= 2.0, sum = 1.0, term;
    	while ( deno <= 100 )
    	{
    		sign	= -sign;
    		term	= sign / deno;
    		sum	+= term;
    		deno	+= 1;
    	}
    	printf( "The output is:%f\n", sum );
    }

The results are as follows:

Exercise 1: Input 10 numbers in turn and output the maximum value

#include <stdio.h>
int main()
{
	int n = 1, max, a;
	printf( "Enter ten numbers:" );
	while ( n <= 10 )
	{
		scanf( "%d", &a );
		if ( a > max )
			max = a;
		n++;
	}
	printf( "max=%d\n", max );
}

The results are as follows:

Exercises 2 and 3 from small to large output

#include <stdio.h>
int main()
{
	int a, b, c, t;
	printf( "Input three numbers:" );
	scanf( "%d%d%d", &a, &b, &c );
	if ( a > b )
	{
		t	= a;
		a	= b;
		b	= t;
	}
	if ( a > c )
	{
		t	= a;
		a	= c;
		c	= t;
	}
	if ( b > c )
	{
		t	= b;
		b	= c;
		c	= t;
	}
	printf( "%d %d %d\n", a, b, c );
}

The results are as follows:

Exercise 3: 1 + 2 + 3 * 100

#include <stdio.h>
int main()
{
	int i, sum = 0;
	for ( i = 1; i <= 100; i++ )
		sum = sum + i;
	printf( "The result is:%d\n", sum );
}

The results are as follows.

Exercise 4 after class to determine whether a number can be divided by three and five at the same time

#include <stdio.h>
int main()
{
	int i;
	printf( "Enter a number:" );
	scanf( "%d", &i );
	if ( i % 3 == 0 && i % 5 == 0 )
		printf( "\n Can be divisible at the same time\n" );
	else
		printf( "\n Not divisible at the same time\n" );
}

The results are as follows:

Exercise 5 will output prime numbers between 100 and 200

#include <stdio.h> 
int main() 
{ 
	int i,j;
	int count=0; 
	for (i=101; i<=200; i++)
	{ 
		for (j=2; j<i; j++)
		{ 	  if (i%j==0) break; 
		}
			
		if (j>=i) 
		{ 
			count++; printf("%d ",i); 
	
		if (count % 5 == 0)
			printf("\n");
		}
	}
}

The results are as follows:

Exercise 6 Finding the Maximum Common Number of Two Numbers m and n

#include <stdio.h>
int main()
{
	int m, n, t;
	printf( "Enter two numbers:" );
	scanf( "%d%d", &m, &n );
	if ( m < n )
	{
		t	= n;
		n	= m;
		m	= t;
	}
	t = m % n;
	while ( t != 0 )
	{
		m	= n;
		n	= t;
		t	= m % n;
	}
	printf( "Maximum common denominator%d\n", n );
}

The results are as follows: