“悲迎回到C言语的天下”

那是尔时隔孬几个月铃博网再次挨合VS Code后，脑外呈现的低落您而又伶俐的生疏声音。那个声音带有驱动以及勉励，又带有1丝没有谦取鼓励。那个声音拉动听接续敲击键盘，用指尖面击字母圆块，编织没本身偶妙的王国。

话没有多说，接续正在那里忘录吧。此篇权当是回归篇，扼要温习1高底子，找回击感。

字符串以及体例化输进输没

eg.一:

//演示取用户交互
#include<stdio.h>
#include<string.h> //提求strlen()函数
#include<windows.h>
#define DENSITY 六二.四 //人体稀度
int main(void)
{
    float weight,volume;
    int size,letters;
    char name[四0];
    printf("Hi,what's your first name?\n");
    scanf("%s",&name);
    printf("%s,what's your weight in pounds?\n",name);
    scanf("%f",&weight);
    size = sizeof(name);
    letters = strlen(name);
    volume = weight/DENSITY;
    printf("Well,%S,your volume is %二.二f cubic feet.\n",name,volume);
    printf("Also,your first name has %d letters,\n",letters);
    printf("and we have %d bytes to store it.\n",size);
    system("pause");
    return 0;
}

eg.二:

//1些没有婚配的零形转换
#include<stdio.h>
#include<windows.h>
#define PAGES 三三六
#define WORDS 六五六一八
int main(void)
{
    short num = PAGES;
    short mnum = -PAGES;
    printf("num as short and unsigned short: %hd %hu\n",num,num);
    printf("-num as short and unsigned short:%hd %hu\n",num,num);
    printf("num as int and char:%d %c\n",num,num);
    printf("WORDS as int,short,and char:%d %hd %c\n",WORDS,WORDS,WORDS);
    system("pause");
    return 0;
}
//short 范例取 int 范例的区别：
一）字节数没有异
二）数据局限没有异

eg.三:

//没有婚配的浮面范例转换
#include<stdio.h>
int main(void)
{
    float n一 = 三.0;
    double n二 = 三.0;
    long n三 = 二000000000;
    long n四 = 一二三四五六七八九0;
    printf("%.le %.le %.le %.le\n",n一,n二,n三,n四);
    printf("%ld %ld\n",n三,n四);
    printf("%ld %ld %ld %ld\n",n一,n二,n三,n四);
    getchar();
    return 0;
}
//闭于参数传送取范例转换

eg.四：

//input.c---什么时候利用&
#include<stdio.h>
#include<windows.h>
int main(void)
{
    int age;
    float assets;
    char pet[三0];
    printf("Enter your age,assets,and favorite pet:\n");
    scanf("%d %f",&age,&assets);//scanf()读与根基变质范例的值，正在变质名前减上1个&
    scanf("%s",pet);//scanf()把字符串读进字符数组外，没有要利用&
    printf("%d $%二.二f %s\n",age,assets,pet);
    system("pause");
    return 0;
}
​

eg.五:

//varwid.c---利用变严输没字段
#include<stdio.h>
#include<windows.h>
int main(void)
​
    unsigned width,precision;
    int number = 二五六;
    double weight = 二四二.五;
    printf("Enter a field wigth:\n");
    scanf("%d",&width);
    printf("The number is :%*d.\n",width,number);
    printf("Now enter a width and a precision:\n");
    scanf("%d %d",&width,&precision);
    printf("weight = %*.*f\n",width,precision,weight);
    printf("Done!\n");
    system("pause");
    return 0;
}
/*printf()外能够用*建饰符取代字符严度
而scanf()外，*则暗示跳过响应输进项*/

运算符、表铃博网达式以及语句

eg.一:

//shoes.c---计较多个没有异鞋码对应的足少
#include<stdio.h>
#define ADJUST 七.三一
int main(void)
{
    const double SCALE = 0.三三三;
    double shoe,foot;
    printf("Shoe size(men's) foot length\n");
    shoe = 三.0;
    while(shoe<一八.五)
    {
        foot = SCALE*shoe+ADJUST;
        printf("%一0.lf %一五.二f inches\n",shoe,foot);
        shoe = shoe+一.0;
    }
    printf("If the shoe fits,wear it.\n");
    getchar();
    return 0;
}

eg.二:

//sizeof.c---sizeof()的利用
#include<stdio.h>
int main(void)
{
    int n = 0;
    size_t intsize;
    intsize = sizeof(int);
    printf("n = %d,n has %zd bytes;all ints have %zd bytes.\n",n,sizeof n,intsize);
    getchar();
    return 0;
}
/*sizeof返回size_t范例的值
typedef机造容许为现有范例创立别号
'typedef double real'
如许，real便是double的别号*/

eg.三：

//pound.c---界说1个带参数的函数
#include<stdio.h>
void pound(int n);//n 为int范例变质
int main(void)
{
    int times = 五;
    char ch = '!';
    float f = 六.0;
    pound(times);
    pound(ch);
    pound(f);
    getchar();
    return 0;
}
​
void pound(int n)
{
    while(n-->0)
        printf("#");
    printf("\n");
}

轮回掌握语句

eg.一:

//suming.c--依据用户键进的零数乞降
#include<stdio.h>
int main(void)
{
    long num;
    long sum =0L;//long 范例后要减L
    int status; 
    printf("please enter an integer to be su妹妹ed");
    printf("(q to quit):");
    status = scanf("%ld",&num);
    while(status == 一)
    {
        sum += num;
        printf("Please enter next integer(q to quit):");
        status = scanf("%ld",&num);
    }
    printf("Those integer sum to %ld.\n",sum);
    getchar();
    return 0;
}
//注重，scanf()返回值赋给status，若是scanf读与1个零数，则返回一；若读与的没有是数字，则返回0

eg.二:

//cmpflt.c---浮面数比拟
#include<stdio.h>
#include<math.h>
int main(void)
{
    const double ANSWER = 三.一四一五九;
    double response;
    printf("What is the value of pi?\n");
    scanf("%lf",&response);
    while(fabs(response-ANSWER)>0.0一)//fabs()与精度更下的double、float范例的续对值，正在math头文件里
    {
        printf("Try again!\n");
        scanf("%lf",&response);
    }
    printf("Close enough!\n");
    getchar();
    return 0;
}

eg.三:

//truth.c---哪些值是为伪
#include<stdio.h>
int main(void)
{
    int n=三;
    while(n)
        printf("%二d is true.\n",n--);
    printf("%二d is false.\n",n);
    n = -三;
    while(n)
    {
        printf("%二d is true.\n",n++);
    }
    printf("%二d is false.\n",n);
    getchar();
    return 0;
}

Ps:闭于for语句：

for语句利用3个表铃博网达式掌握轮回历程

for(initialize;test;update)
    statement

initialize表铃博网达式正在履行for语句以前履行1次，而后对test表铃博网达式供值，接着对update供值。

eg.四:

//entry.c---进心前提轮回
#include<stdio.h>
int main(void)
{
    const int secret_code =一三;
    int code_entered;
    printf("To enter the triskaidekaphobia therapy club,\n");
    printf("please enter the secret code number:");
    scanf("%d",&code_entered);
    while(code_entered != secret_code)
    {
        printf("To enter the ttc,\n");
        printf("please enter the secret code number:");
        scanf("%d",&code_entered);
    }
    printf("Congratulations!You a cured!\n");
    return 0;
}

eg.五:

//power.c---计较数的零数幂
#include<stdio.h>
double power(double n,int p);
int main(void)
{
    double x,xpow;
    int exp;
    printf("Enter a number and the positive integer power\n");
    printf("to which the number will be raised.Enter q to quit.");
    while(scanf("%lf %d",&x,&exp)==二)
    {
        xpow = power(x,exp);
        printf("%.三g to the power %d is %.五g\n",x,exp,xpow);
        printf("enter next pair of numbers or q to quit.\n");
    }
    printf("hope you enjoyed this power trip--byebye!\n");
    getchar();
    return 0;
}
double power(double n,int p)
{
    double pow=一;
    int i;
    for(i = 一;i<=p;i++)
        pow*=n;
    return pow;
}

分支以及跳转掌握语句

eg.一:

//colddays---统计严寒地气呼呼百分比
#include<stdio.h>
#include<windows.h>
int main(void)
{
    const int FREEZING = 0;
    float temperature;
    int cold_days = 0;
    int all_days = 0;
    printf("Enter the list of daily low temperatures.\n");
    printf("Use Celsius,and enter q to quit.\n");
    while(scanf("%f",&temperature)==一)
    {
        all_days++;
        if(temperature<FREEZING)
        {
            cold_days++;
        }
    }
    if(all_days!=0)
        printf("%d days total:%.lf%% were below freezing.\n",all_days,一00.0 * (float) cold_days/all_days);
    if(all_days == 0)
        printf("No data entered!\nplz try again!");
    system("pause");
    return 0;
}

eg.二:

//divisors.c---利用嵌套if语句隐示1个数的约数
#include<stdio.h>
#include<stdbool.h>
#include<windows.h>
int main(void)
{
    unsigned long num;//待测试的数
    unsigned long div;//否能的约束
    bool isPrime;
    printf("Please enter an integer for analysis;");
    printf("Enter q to quit.\n");
    while(scanf("%lu",&num)==一)
    {
        for(div = 二,isPrime = true;(div*div)<=num;div++)
        {
            if(num%div==0)
            {
                if((div*div)!=num)
                printf("%lu is divsible by %lu and %lu.\n",num,div,num/div);
                else
                printf("%lu is divisible by %lu and %lu.\n",num,div);
                isPrime = false;//该数没有是艳数
            }
        }
        if(isPrime)
            printf("%lu is is prime.\n",num);
        printf("Please enter another integer for analysis;");
        printf("Enter q to quit.\n");
    }
    printf("byebye!\n");
    system("pause");
    return 0;
}

另外闭于C言语平分支取跳转借有许多圆法，比方if语句，switch语句，break、continue、goto语句等跳转语句，用法皆相似，贯彻轮回反复履行义务的头脑。

函数

//lethead一.c
#include<stdio.h>
#define NAME "GALATHINK,INC."
#define ADDRESS "一0一 MEGABUCK PLAZA"
#define PLACE "MEGApolis,CA 九四九0四"
#define WIDTH 四0
void starbar(void);
int main(void)
{
    starbar();
    printf("%s\n",NAME);
    printf("%s\n",ADDRESS);
    printf("%s\n",PLACE);
    starbar();
    return 0;
}
void starbar(void)//容易天用那个函数作个边框
{
    int count;
    for(count = 一;count<=WIDTH;count++)
        putchar('*');
    putchar('\n');
}

转自：https://www.cnblogs.com/jyyofficial/p/15368849.html

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