Niuke C basic exercises

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Preface

Hello, everyone ！ I am a vince, In the process of learning programming language, you should find , The theoretical basis is very important , Then it is more important to actually operate the machine , The computer operation is nothing more than writing project code , More of course is to brush questions ~ Then at this time, a good question brushing website is really very important , It will make you go in the right direction , Clear learning ideas , therefore , ad locum Recommend a study to the little friends who love learning 、 The website of question brushing, Niuke , There are all kinds of interview questions , It can really bring you a good learning experience .

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The following is the Niuke question bank interface ：

Next , Let's get down to business , Let's take a look at some related examples .

Text

Topic 1 ： Niuniu line segment

describe Niuniu has a line segment placed in a two-dimensional coordinate system , The coordinates of two points of a given line segment (x1,y1),(x2,y2) . Niuniu wants to know the square of the length of this line segment

Input description ： First line input x1 and y1, Space off . Second line input x2 and y2, Space off . among x1 , y1 ,x2 ,y2 Are integers.

Output description ： The square of the length of the output line segment

The code is as follows ：

#include <stdio.h>
#include <math.h>

int main(void)
{
    
    int x1 = 0, x2 = 0;
    int y1 = 0, y2 = 0;
    scanf("%d %d",&x1, &y1);
    scanf("%d %d",&x2, &y2);
    int ret = pow((x1-x2),2)+pow((y1-y2),2);
    printf("%d\n",ret);
}

summary ：

Note that you need to examine the question carefully , The problem is to find its square .

Topic two ： Pass score

describe KiKi I want to know if he passed the exam , Please help him judge . Enter a fraction represented by an integer from the keyboard , Program to determine whether the score is within the pass range , If you pass , namely ： A score greater than or equal to 60 branch , It's output “Pass”, otherwise , Output “Fail”.

Input description ： Multi group input , Each line of input includes a fraction represented by an integer （0~100）.

Output description ： Enter... For each line , Output “Pass” or “Fail”.

The code is as follows ：

#include <stdio.h>

int main(void)
{
    
    int n = 0;
    while(scanf("%d",&n)!=EOF)
    {
    
        if(n>=60)
        {
    
            printf("Pass\n");
        }
        else
        {
    
            printf("Fail\n");
        }
    }
}

summary ：

Start here C The branch structure of , Slowly walk into C The theme of ！
There are multiple sets of inputs for this question , So pay attention when typing the code ！

Topic three ： Judge integer parity

describe KiKi Want to know the parity of an integer , Please help him judge . Enter any integer from the keyboard （ Range -231~231-1）, Program to judge its parity .

Input description ： Multi group input , Each line of input includes an integer .

Output description ： Enter... For each line , The output number is odd （Odd） Or even （Even）.

The code is as follows ：

#include<stdio.h>
int main()
{
    
    int n=0;
    while(~scanf("%d",&n))
    {
    
        if(n%2==0)
        {
    
            printf("Even\n");
        }
        else
        {
    
            printf("Odd\n");
        }
    }
    return 0;
}

Topic four ： Determine whether vowels or consonants

describe KiKi Start learning English letters ,BoBo The teacher told him , There are five letters A(a), E(e), I(i), O(o),U(u) Called vowels , All other letters are called consonants , Please help him write a program to judge whether the input letter is a vowel （Vowel） Or consonants （Consonant）.

Input description ： Multi group input , Enter one letter per line .

Output description ： Enter... For each group , Output as a line , If the input letter is a vowel （ Include case ）, Output “Vowel”, If the input letter is a non vowel , Output “Consonant”.

The code is as follows ：

#include<stdio.h>
#include<ctype.h>

int main()
{
    
    char letter = 0;
    while (scanf(" %c", &letter)!=EOF)//%c If a space is added in front of it, it is to eliminate carriage return 
    {
    
        //getchar();// If there is no preceding space, eliminate carriage return , Just use getchar Eliminate spaces 
        letter = toupper(letter);// This function converts lowercase letters to uppercase letters 
        switch (letter)
        {
    
        case 'A':
        case 'E':
        case 'I':
        case 'O':
        case 'U':printf("Vowel\n"); break;
        default:printf("Consonant\n");
        }
    }
    return 0;
}

summary ：

There are two strange knowledge points in this problem ：
1、 First comes the use of getchar() Function to eliminate carriage returns , Here to %c Adding a space in front also meets the format requirements of this topic , But we need to learn getchar() Function to eliminate the use of carriage return ！
2、 It's here toupper() function , The function is ： Convert lowercase letters to their corresponding uppercase letters .

Topic 5 ： Niuniu's judgment question

describe Niu Niu inputs an integer from the keyboard x And the left and right boundaries l and r Three integers in total . Please judge x Whether in l and r Between （ That is, whether there is l≤x≤r ）

Input description ： Input in sequence x ,l ,r Three integers . Space off .

Output description ： If there is l≤x≤r The output true , Otherwise output false

The code is as follows ：

#include <stdio.h>

int main(void)
{
    
    int x = 0, l = 0, r = 0;
    scanf("%d %d %d",&x,&l,&r);
    if(x >= l && x <= r)
        printf("true\n");
    else
        printf("false\n");
}

Topic 6 ： Judgement of leap year

describe Judge an integer n Is it a leap year

Input description ： Enter an integer n （1≤n≤2018）

Output description ： Is leap year output "yes" Otherwise output "no"

The code is as follows ：

#include<stdio.h>

int main(void)
{
    
    int n = 0;
    scanf("%d",&n);
    if(n % 4 == 0 && n % 100 != 0 || n % 400 == 0)
        printf("yes\n");
    else
        printf("no\n");
}

summary ：

In this problem, we need to remember the conditions for judging leap years ：(n % 4 == 0 && n % 100 != 0 || n % 400 == 0).

Topic 7 ： Judging letters

describe Enter any character from the keyboard , Program to determine whether it is a letter （ Include case ）.

Input description ： The input includes one character .

Output description ： The output character is a letter （YES） Or not （NO）.

The code is as follows ：

#include<stdio.h>
int main(void)
{
    
	char n = 0;
	scanf("%c", &n);
	if (n >= 'a' && n <= 'z' || n>='A' && n <= 'Z')
	{
    
		printf("YES\n");
	}
	else
	{
    
		printf("NO\n");
	}
}

Topic 8 ： The four seasons

describe In the meteorological sense , Usually, the 3～5 The month is spring (spring),6～8 The month is summer (summer),9～11 The month is autumn (autumn),12 month ～ Coming year 2 The month is winter (winter). Please enter the year and month according to , Output the corresponding season .

Input description ： The input data format is fixed YYYYMM In the form of , namely ： The year accounts for 4 One digit , Month share 2 One digit .

Output description ： Output the season corresponding to the month （ Use English words to express , All in lowercase ）.

The code is as follows ：

#include <stdio.h>

int main(void)
{
    
    int m = 0;
    scanf("%d",&m);
    int n = m % 100;
    switch(n)
    {
    
        case 3:
        case 4:
        case 5:printf("spring\n");break;
        case 6:
        case 7:
        case 8:printf("summer\n");break;
        case 9:
        case 10:
        case 11:printf("autumn\n");break;
        default:printf("winter\n");
    }
}

Topic nine ： Health assessment

describe BMI Index （ Body mass index ） It's the number of kilograms divided by the square of meters of height , At present, it is a standard commonly used in the world to measure the degree of weight and health . for example ： A person's height is 1.75 rice , The weight is 68 kg , His BMI=68/(1.75^{2)=22.2（ kg / rice} 2）. When BMI Index is 18.5～23.9 Time is normal , Otherwise, it means that there is a health risk to the body . Program to judge human health .

Input description ： a line , Enter a person's weight （ kg ） And height （ rice ）, Separated by a space .

Output description ： a line , Output body Normal( normal ) or Abnormal( Is not normal ).

The code is as follows ：

#include<stdio.h>
int main(void)
{
    
    double m = 0,n = 0;
    double BMI = 0;
    scanf("%lf %lf",&m,&n);
    BMI = m / (n*n);
    if(BMI >= 18.5 && BMI <= 23.9)
    {
    
        printf("Normal\n");
    }
    else
    {
    
        printf("Abnormal\n");
    }
}

Topic ten ： Xiaolele looks for the largest number

describe Xiaolele gets 4 The maximum number , Please help him program to find the maximum number .

Input description ： a line ,4 It's an integer , Separate with spaces .

Output description ： a line , An integer , For input 4 The largest of the integers .

Code (1) as follows ：

#include <stdio.h>

int main(void)
{
    
    int n = 0;
    int max = 0;
    while(scanf("%d",&n) != EOF)
    {
    
        if(max < n)
        {
    
            max = n;
        }
    }
    printf("%d\n",max);
}

Code (2) as follows ：
Use the combination of array and ternary operator to judge

#include <stdio.h>

int main(void)
{
    
    int arr[4] = {
    0};
    for(int i = 0; i < 4; i++)
    {
    
        scanf("%d",&arr[i]);
    }
    int max = 0;
    for(int i = 0; i < 4; i++)
    {
    
        max = max < arr[i] ? arr[i] : max;
    }
    printf("%d\n",max);
}

Conclusion

A good learning environment is really very important , This is of great help to your study , Niuke is one of the good learning environments , If you haven't experienced it yet, go and experience it Study loving relatives ！ Please click on me to register ！ Study 、 Brush problem
Niuke review exercise , Coders must type more code , Step back from the basic question type , From qualitative change to quantitative change , come on. ！
I also hope you can find some inspiration from these topics , If there are deficiencies or other methods , Please type in the comment area ~ learn from each other , Make progress with each other ~
Goodbye ！
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