程序設計基礎(C)第04講例程

1 talkback.c

// talkback.c -- nosy, informative program
#include <stdio.h>
#include <string.h>      // for strlen() prototype
#define DENSITY 62.4     // human density in lbs per cu ft
int main()
{
    float weight, volume;
    int size, letters;
    char name[40];        // name is an array of 40 chars
    
    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 %2.2f 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);
    return 0;
}

2 praise1.c

/* praise1.c -- 使用不一樣類型的字符串 */
#include <stdio.h>
#define PRAISE "You are an extraordinary being."
int main(void)
{
    char name[40];
    
    printf("What's your name? ");
    scanf("%s", name);
    printf("Hello, %s. %s\n", name, PRAISE);
    
    return 0;
}

3 praise2.c

/* praise2.c */
// try the %u or %lu specifiers if your implementation
// does not recognize the %zd specifier
#include <stdio.h>
#include <string.h>      /* provides strlen() prototype */
#define PRAISE "You are an extraordinary being."
int main(void)
{
    char name[40];
    
    printf("What's your name? ");
    scanf("%s", name);
    printf("Hello, %s. %s\n", name, PRAISE);
    printf("Your name of %zd letters occupies %zd memory cells.\n",strlen(name), sizeof name);
    printf("The phrase of praise has %zd letters ",strlen(PRAISE));
    printf("and occupies %zd memory cells.\n", sizeof PRAISE);
    
    return 0;
}

4 pizza.c

/* pizza.c -- 在比薩餅程序中使用已定義的常量  */
#include <stdio.h>
#define PI 3.14159
int main(void)
{
    float area, circum, radius;
    
    printf("What is the radius of your pizza?\n");
    scanf("%f", &radius);
    area = PI * radius * radius;
    circum = 2.0 * PI *radius;
    printf("Your basic pizza parameters are as follows:\n");
    printf("circumference = %1.2f, area = %1.2f\n", circum,area);
    return 0;
}

5 defines.c

// defines.c --使用limit.h和float頭文件中定義的明示常量
#include <stdio.h>
#include <limits.h>    // integer limits
#include <float.h>     // floating-point limits
int main(void)
{
    printf("Some number limits for this system:\n");
    printf("Biggest int: %d\n", INT_MAX);
    printf("Smallest long long: %lld\n", LLONG_MIN);
    printf("One byte = %d bits on this system.\n", CHAR_BIT);
    printf("Largest double: %e\n", DBL_MAX);
    printf("Smallest normal float: %e\n", FLT_MIN);
    printf("float precision = %d digits\n", FLT_DIG);
    printf("float epsilon = %e\n", FLT_EPSILON);
    
    return 0;
}

6 printout.c

/* printout.c -- 使用轉換說明  */
#include <stdio.h>
#define PI 3.141593
int main(void)
{
    int number = 7;
    float pies = 12.75;
    int cost = 7800;

    
    printf("The %d contestants ate %f berry pies.\n", number,pies);
    printf("The value of pi is %f.\n", PI);
    printf("Farewell! thou art too dear for my possessing,\n");
    printf("%c%d\n", '$', 2 * cost);
    
    return 0;
}

7 width.c

/* width.c -- 字段寬度  */
#include <stdio.h>
#define PAGES 959
int main(void)
{
    printf("*%d*\n", PAGES);
    printf("*%2d*\n", PAGES);
    printf("*%10d*\n", PAGES);
    printf("*%-10d*\n", PAGES);
    
    return 0;
}

8 floats.c

// floats.c -- 一些浮點型修飾符的組合
#include <stdio.h>

int main(void)
{
    const double RENT = 3852.99;  // const-style constant
    
    printf("*%f*\n", RENT);
    printf("*%e*\n", RENT);
    printf("*%4.2f*\n", RENT);
    printf("*%3.1f*\n", RENT);
    printf("*%10.3f*\n", RENT);
    printf("*%10.3E*\n", RENT);
    printf("*%+4.2f*\n", RENT);
    printf("*%010.2f*\n", RENT);
    
    return 0;
}

9 flags.c

/* flags.c -- 演示一些格式標記  */
#include <stdio.h>
int main(void)
{
    printf("%x %X %#x\n", 31, 31, 31);
    printf("**%d**% d**% d**\n", 42, 42, -42);
    printf("**%5d**%5.3d**%05d**%05.3d**\n", 6, 6, 6, 6);
    
    return 0;
}

10 stringf.c

/* stringf.c -- 字符串格式  */
#include <stdio.h>
#define BLURB "Authentic imitation!"
int main(void)
{
    printf("[%2s]\n", BLURB);
    printf("[%24s]\n", BLURB);
    printf("[%24.5s]\n", BLURB);
    printf("[%-24.5s]\n", BLURB);
    return 0;
}

11 intconv.c

/* intconv.c -- 一些不匹配的整型轉換  */
#include <stdio.h>
#define PAGES 336
#define WORDS 65618
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", mnum,mnum);
    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);
    return 0;
}

12 floatcnv.c

/* floatcnv.c -- 不匹配的浮點型轉換  */
#include <stdio.h>
int main(void)
{
    float n1 = 3.0;
    double n2 = 3.0;
    long n3 = 2000000000;
    long n4 = 1234567890;
    
    printf("%.1e %.1e %.1e %.1e\n", n1, n2, n3, n4);
    printf("%ld %ld\n", n3, n4);
    printf("%ld %ld %ld %ld\n", n1, n2, n3, n4);
    
    return 0;
}

13 prntval.c

/* prntval.c --  printf()的返回值 */
#include <stdio.h>
int main(void)
{
    int bph2o = 212;
    int rv;
    
    rv = printf("%d F is water's boiling point.\n", bph2o);
    printf("The printf() function printed %d characters.\n",rv);
    return 0;
}

14 longstrg.c

/* longstrg.c –– 打印較長的字符串 */
#include <stdio.h>
int main(void)
{
    printf("Here's one way to print a ");
    printf("long string.\n");
    printf("Here's another way to print a \long string.\n");
    printf("Here's the newest way to print a ""long string.\n");      /* ANSI C */
    
    return 0;
}

15 input.c

// input.c -- 什麼時候使用&
#include <stdio.h>
int main(void)
{
    int age;             // variable
    float assets;        // variable
    char pet[30];        // string
    
    printf("Enter your age, assets, and favorite pet.\n");
    scanf("%d %f", &age, &assets); // use the & here
    scanf("%s", pet);              // no & for char array
    printf("%d $%.2f %s\n", age, assets, pet);
    
    return 0;
}

16 varwid.c

/* varwid.c -- 使用變寬輸出字段  */
#include <stdio.h>
int main(void)
{
    unsigned width, precision;
    int number = 256;
    double weight = 242.5;
    
    printf("Enter a field width:\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");
    
    return 0;
}

17 skiptwo.c

/* skiptwo.c --  跳過輸入中的前兩個整數 */
#include <stdio.h>
int main(void)
{
    int n;
    
    printf("Please enter three integers:\n");
    scanf("%*d %*d %d", &n);
    printf("The last integer was %d\n", n);
    
    return 0;
}