1. Insert a number into an array that has been arranged in ascending order. After inserting, the array elements are still arranged in ascending order

#include<stdio.h>
#define	N 10
void fun(int *a)
{
	int number,i;
	printf("Please enter a integer to insert in the array:");
	scanf("%d", &number);
	for (i = N - 2; i >= 0; i--)
	{
		if (number <= *(a + i))
		{
			*(a + i + 1) = *(a + i);
		}
		else
		{
			*(a + i + 1) = number;
			break;
		}
	}
	if (number < *a)
	{
		*a = number;
	}
	printf("The result array:");
	for (i = 0; i < N; i++)
	{
		printf("%5d", *(a + i));
	}
	printf("\n");
}

void main()
{
	int number;
	int i;
	int a[N] = { 11,22,33,44,55,66,77,88,99 };
	printf("The original array:");
	for (i = 0; i < N-1; i++)
	{
		printf("%5d", *(a+i));
	}
	printf("\n");
	fun(a);
}

 

2. Function comb(char *a,char *b) reverses string a, and then appends string B at the end

#include<stdio.h>
#include<string.h>
void comb(char *a, char *b)
{
	int i, j;
	int len = strlen(a);
	char c;
	for (i = 0; i < len / 2; i++)
	{
		c = *(a + i);
		*(a + i) = *(a + len - i - 1);
		*(a + len - i - 1) = c;
	}
	*(a + len++) = ' ';
	j = 0;
	while (*(a + len + j) = *(b + j++));
}

void main()
{
	char a[100] = "margorP C";
	char b[] = "Design";
	comb(a, b);
	printf("%s\n", a);
}

 

3. Input 10 elements of one-dimensional array, exchange with a[9] the largest, exchange with a[0] the smallest, and output 10 elements of array

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
void input(int number[])
{
	int i;
	for (i = 0; i < 10; i++)
	{
		scanf("%d", &number[i]);
	}
}

void max_min(int array[])
{
	int *max, *min;
	int *p, *arr_end;
	arr_end = array + 10;
	max = min = array;
	for (p = array + 1; p < arr_end; p++)    //The address p points to array[10] after the for loop ends
	{
		if(*p>*max)
		{
			max = p;
		}
		else if(*p<*min)
		{
			min = p;
		}
	}
	
	*p = array[0];    //Exchange with array[10]
	array[0] = *min;
	*min = *p;
	
	*p = array[9];
	array[9] = *max;
	*max = *p;
}

void output(int array[]) 
{
	int *p;
	for (p = array; p < array + 10; p++)
	{
		printf("%d ",*p);
	}
}

void main()
{
	int number[11];
	input(number);
	printf("\n");
	max_min(number);
	output(number);
}

 

4. Output the larger number of two integers, which are input by keyboard

#include<stdio.h>
#include<stdlib.h>
void main()
{
	int *p1, *p2;
	p1 = (int*)malloc(sizeof(int));
	p2 = (int*)malloc(sizeof(int));
	scanf("%d%d", p1, p2);
	if (*p2 > *p1)
	{
		*p1 = *p2;
	}
	free(p2);
	printf("%d\n", *p1);
	free(p1);
}

 

5. Delete the numeric characters in the string

#include<stdio.h>
#include<string.h>
void fun(char *s)
{
	char *p = s;
	while (*p)
	{
		if ((*p >= '0') && (*p <= '9'))
		{
			p++;
		}
		else
		{
			*(s++) = *(p++);
		}
	}
	*s = '\0';
}
void main()
{
	char item[100];
	printf("Enter a string:");
	gets_s(item);
	fun(item);
	printf("%s\n", item);
}

 

6. Connect the positive and negative order of the string indicated by s to form a new string and put it in the array indicated by t

#include<stdio.h>
#include<string.h>
void fun(char *s,char *t)
{
	int i, d;
	d = strlen(s);
	for (int i = 0; i < d; i++)
	{
		t[i] = s[i];
	}
	for (int i = 0; i < d; i++)
	{
		t[i + d] = s[d - 1 - i];
	}
	t[2 * d] = '\0';
}
void main()
{
	char s[100], t[100];
	printf("Please enter string:");
	scanf("%s", s);
	fun(s, t);
	printf("\nThe result is:%s\n", t);
}

 

7. Receive a string from the keyboard, and sort it from small to large, and delete the duplicate characters

#include<stdio.h>
#include<string.h>
void main()
{
	char str[100], *p, *q, *r, c;
	printf("Input string:");
	gets_s(str);
	for (p = str; *p; p++)
	{
		for (q = r = p; *q; q++)
		{
			if (*r > *q)
			{
				r = q;
			}
		}
		if (r != p)
		{
			c = *r;
			*r = *p;
			*p = c;
		}
	}
	for (p = str; *p;p++)
	{
		for (q = p+1 ; *p == *q;)
		{
			strcpy(p, q);    //After using strcpy, q points to the address of the next string element, so the for loop above does not write q++
		}
	}
	printf("Result string:%s\n", str);
}

 

 

8. Count the number of words in the string

#include<stdio.h>
int wordCount(char *s)
{
	int num = 0,i,word=0;
	while (*s != '\0')
	{
		if (*s == ' ')
		{
			word = 0;
		}
		else if (word == 0)
		{
			word = 1;
			num++;
		}
		s++;
	}
	return(num);
}
void main()
{
	char str[101];
	int wordnum;
	printf("Enter a string of no more than 100 characters:");
	gets_s(str);
	wordnum = wordCount(str);
	printf("Yes%d Word\n", wordnum);
}

 

9. Output the second row element of a two-dimensional array with three rows and five columns

#include<stdio.h>
void main()
{
	int a[3][5],i,j;
	printf("please input:\n");
	for (i = 0; i < 3; i++)
	{
		for (j = 0; j < 5; j++)
		{
			scanf("%d", *(a + i) + j);
		}
	}
	printf("The second line is:");
	for (j = 0; j < 5; j++)
	{
		printf("%5d", *(*(a + 1) + j));
	}
	printf("\n");
}