c primer plus 8编程练习

 

1、

#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    int ch;
    FILE * fp;
    char filename[128];
    int sum = 0;
    
    printf("please input filename: ");
    scanf("%s", filename);
    
    fp = fopen(filename, "r");
    
    if(fp == NULL)
    {
        printf("file failed opened!\n");
        exit(1);
    }
    
    while((ch = getc(fp)) != EOF)
    {
        putchar(ch);
        sum++;
    }
    
    printf("\nsum: %d.\n", sum);
    
    return 0;
}

 

#include <stdio.h>

int main(void)
{
    char ch;
    int sum = 0;
    
    while((ch = getchar()) != EOF)
    {
        putchar(ch);
        sum++;
    }
    
    printf("sum: %d.\n", sum);
    
    return 0;
}

 

#include <stdio.h>

int main(void)
{
    char ch;
    int sum = 0;
    
    while((ch = getchar()) != EOF)
    {
        putchar(ch);
        if(ch > '\040')
            sum++;
    }
    
    printf("sum: %d.\n", sum);
    
    return 0;
}

 

#include <stdio.h>

int main(void)
{
    char ch;
    int sum = 0;
    
    while((ch = getchar()) != EOF)
    {
        putchar(ch);
        if(ch == '\n')
            sum++;
    }
    
    printf("sum: %d.\n", sum);
    
    return 0;
}

 

2、

#include <stdio.h>

int main(void)
{
    int counter = 0;
    char ch;
    
    while((ch = getchar()) != EOF)
    {
        if(counter++ == 10)
        {
            printf("\n");
            counter = 1;
        }
        if(ch >= '\040')
        {
            printf(" \'%c\'--%3d ", ch, ch);    
        }
        else if(ch == '\n')
        {
            printf(" \\n--\\n ");
            counter = 0;
        }
        else if(ch == '\t')
        {
            printf(" \\t--\\t ");
        }
        else
        {
            printf(" \'%c\'--^%c ", ch, (ch + 64));
        }
    }    
    
    return 0;
} 

 

#include <stdio.h>

int main(void)
{
    int counter = 0;
    char ch;
    
    while((ch = getchar()) != EOF)
    {
        if(counter++ == 10)
        {
            printf("\n");
            counter = 1;
        }
        if(ch >= '\040')
        {
            printf(" \'%c\' -- %3d  ", ch, ch);
        }
        else if(ch == '\n')
        {
            printf(" \\n - \\n ");
        }
        else if(ch == '\t')
        {
            printf(" \\t -- \\t ");
        }
        else
        {
            printf(" %c -- %d. ", ch, (ch + 64));
        }
    }
    return 0;
}

 

3、

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

int main(void)
{
    char ch;
    int sum_upper = 0;
    int sum_lower = 0;
    
    while((ch = getchar()) != EOF)
    {
        if(isupper(ch))
            sum_upper++;
        if(islower(ch))
            sum_lower++;
    }
    printf("sum_upper: %d.\n", sum_upper);
    printf("sum_lower: %d.\n", sum_lower);
    
    return 0;
}

 

#include <stdio.h>

int main(void)
{
    char ch;
    int sum_upper = 0;
    int sum_lower = 0;
    
    printf("please input letters: ");
    
    while((ch = getchar()) != EOF)
    {
        if(ch >= 'a' && ch <= 'z')
            sum_lower++;
        if(ch >= 'A' && ch <= 'Z')
            sum_upper++;
    } 
    
    printf("sum_upper: %d.\n", sum_upper);
    printf("sum_lower: %d.\n", sum_lower);
    
    return 0;
}

 

4、

#include <stdio.h>

int main(void)
{
    char ch;
    
    int words = 0;
    int letters = 0;
    
    while((ch = getchar()) != EOF)
    {
        if(ch == ' ' || ch == '\n')
            words++;
        if(ch != ' ' && ch != '\n')
            letters++;
    }
    
    printf("words: %d.\n", words);
    printf("letters: %d.\n", letters);
    printf("average letters: %.2f\n", (double)letters/words);
    
    return 0;    
}

 

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

int main(void)
{
    int ch;
    bool word = false;
    bool space = false;
    int words = 0;
    int letters = 0; 
    
    while((ch = getchar()) != EOF)
    {
        if(!isspace(ch))
            word = true;
        else
            space = true;
        
        if(word && space)
        {
            words++;
            word = false;
            space = false;
        }
        
        if(!word && space)
            space = false;  // 消除连续空格的影响 
        if(isalpha(ch))
            letters++;
    }
    printf("words: %d.\n", words);
    printf("letters: %d.\n", letters);
    printf("average letters per word: %.2f.\n");
    
    return 0;
}

 

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

int main(void)
{
    int ch;
    bool inword = false;
    
    int words = 0;
    int letters = 0;
    
    while((ch = getchar()) != EOF)
    {
        if(!isspace(ch) && !inword)    
        {
            words++;
            inword = true;
        }
        if(isspace(ch) && inword)
            inword = false;
            
        if(isalpha(ch))
            letters++;
    }    
    
    printf("words: %d.\n", words);
    printf("letters: %d.\n", letters);
    printf("letters per words %.2f.\n", (float)letters/words); 
    
    return 0;
} 

 

5、

#include <stdio.h>

char judge(void);

int main(void)
{
    int top = 100;
    int bottom = 0;
    int guess;
    char ch;
    char ch2;
    guess = (top - bottom) /2;
    int tmp;
    
    printf("pick an integer from 1 to 100. I will try to guess ");
    printf("int.\nrespond with a y if my guess is right and with");
    printf("\nan n if it is wrong.\n");
    printf("uh...is your number %d?\n",  guess);
    
    while((ch = getchar()) != 'y')
    {
        if(ch == 'n')
        {
            while(getchar() != '\n')
                continue;
            ch2 = judge();
            
            printf("ch2: %c.\n", ch2);
            if(ch2 == 'b')
            {
                top = guess;
                guess = guess - (guess - bottom)/2;
            }
            else if(ch2 == 's')
            {
                tmp = guess;
                guess = guess + (guess - bottom)/2;
                bottom = tmp;
            }
            else
                break;
            
            printf("well, then, is it %d?\n", guess);
        }
        else
            printf("you can only input n and y: ");
        while(getchar() != '\n')
            continue;
    }
    if(ch2 != 'q')
        printf("i kenw i could do it!\n");
    
    return 0;
}

char judge(void)
{
    char ch;
    
    printf("b mean big; s mean small; q to quit: ");
    
    while((ch = getchar()) != 'q' && ch != 'b' && ch != 's')
    {
        printf("you can only input b, s and q, b mean big, s mean small, q to quit: ");
    }
    
    return ch;
}

 

#include <stdio.h>

int main(void)
{
    int head = 1;
    int tail = 100;
    int guess = (head + tail) / 2;
    char ch;
    printf("pick an integer from 1 to 100. I will try to guess ");
    printf("it.\nresponed with a y if my guess is right and with");
    printf("\nan n if it is wrong.\n");
    do
    {
        printf("un...is your number %d?: ", guess);
        if(getchar() == 'y')
        break;
        printf("well, then, %d is larger or smaller the yours:? (l of s): ", guess);
        while((ch = getchar()) == '\n')
            continue;
        if(ch == 'l' || ch == 'L')
        {
            tail = guess - 1;
            guess = (head + tail) / 2;
            continue;
        }
        else if(ch == 's' || ch == 'S')
        {
            head = guess + 1;
            guess = (head + tail)/2;
            continue;
        }
        else
        continue;
    }
    while(getchar() != 'y');
    
    printf("i knew i could do it!\n");
    
    return 0;
}

 

6、

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

char get_first(void);

int main(void)
{
    int ch;
    
    ch = get_first();
    
    printf("ch: %c.\n", ch);
    
    return 0;
}

char get_first(void)
{
    int ch;
    
    while((ch = getchar()) != EOF)
    {
        if(!isspace(ch))
            break;
    }
    
    while(getchar() != '\n')
        continue;
    return ch;
}

 

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

char get_first(void);

int main(void)
{
    char ch;
    
    ch = get_first();
    
    printf("ch: %c.\n", ch);
    
    return 0;
}

char get_first(void)
{
    char ch;
    
    do
    {
        ch = getchar();
    }
    while(isspace(ch));
    
    return ch;
}

 

7、

#include <stdio.h>
#define OVER_WORK 1.5
#define BASE_TAX 0.15
#define EXTRA_TAX 0.2
#define EXCEED_TAX 0.25
char get_char(void);
void calculat_salary(float time, float price);

int main(void)
{
    char ch;
    float work_time;
    float price;
    
    ch = get_char();
    while(ch != 'q')
    {
        printf("please input your work time a week: ");
        scanf("%f", &work_time);
        while(getchar() != '\n')
            continue;
        switch(ch)
        {
            case 'a': price = 8.75; calculat_salary( work_time,  price); break;
            case 'b': price = 9.33; calculat_salary( work_time,  price); break;
            case 'c': price = 10.00; calculat_salary( work_time,  price); break;
            case 'd': price = 11.20; calculat_salary( work_time,  price); break;
            default: printf("program error.\n"); break;
        }
        putchar('\n');
        ch = get_char();
    }
}
 
char get_char(void)
{
    char ch;
    printf("a) $8.75/hr            b) $9.33/hr\n");
    printf("c) $10.00/hr           d) $11.20/hr\n");
    printf("q) quit/\n");
    printf("please input your choice: ");
    
    while((ch = getchar()) != 'q' && (ch < 'a' || ch > 'd')) 
    {
        printf("\nyou can only input a-d and q.\n");
        printf("a) $8.75/hr            b) $9.33/hr\n");
        printf("c) $10.00/hr           d) $11.20/hr\n");
        printf("q) quit/\n");
        printf("please input again: ");
        while(getchar() != '\n')
            continue;
    }
    
    return ch;
}

void calculat_salary(float time, float price)
{
    float salary_sum;
    float tax;
    float salary_taxed;
    
    if(time <= 40)
    {
        salary_sum = time * price;    
    }
    else
    {
        time = 40 + (time - 40) * OVER_WORK;
        salary_sum = time * price;
    }
    
    if(salary_sum <= 300)
    {
        tax = salary_sum * BASE_TAX;
    }
    else if(salary_sum > 300 && salary_sum <= 450)
    {
        tax = 300 * BASE_TAX + (salary_sum - 300) * EXTRA_TAX; 
    }
    else
    {
        tax = 300 * BASE_TAX + 150 * EXTRA_TAX + (salary_sum - 450) * EXCEED_TAX;
    }
    salary_taxed = salary_sum - tax;
    
    printf("salary_sum: %.2f.\n", salary_sum);
    printf("tax: %.2f.\n", tax);
    printf("salary_taxed: %.2f\n", salary_taxed);
}

 

#include <stdio.h>
#define WORK_OVERTIME 1.5
#define BASE_TAX 0.15
#define EXTRA_TAX 0.20
#define EXCEED_TAX 0.25
void memo(void);
float get_time(void);
void calculate(float time, float price);
char get_char(void);

int main(void)
{
    float worktime;
    float price;
    char choice;
    
    
    do
    {
        memo();
        choice = get_char();
        
        switch(choice)
        {
            case 'a': price = 8.75; worktime = get_time(); calculate(worktime, price); break;
            case 'b': price = 9.33; worktime = get_time(); calculate(worktime, price); break;
            case 'c': price = 10.00; worktime = get_time(); calculate(worktime, price); break;
            case 'd': price = 11.20; worktime = get_time(); calculate(worktime, price); break;
            case 'q': break;    
            default: printf("you can only input a-d and q.\n"); break;
        }    
    }
    while(choice != 'q');
} 

void memo(void)
{
    printf("The options are as bellow.\n");
    printf("a) $8.75/hr            b) $9.33/hr\n");
    printf("c) $10.00/hr           d) $11.20/hr\n");
    printf("q) quit\n");
    printf("please input your choice: ");
}

float get_time(void)
{
    float time;
    char ch;
    printf("please input your work time: ");
    while(scanf("%f", &time) != 1)
    {
        while((ch = getchar()) != '\n')
            putchar(ch);
        printf(" is not num.\n");
        printf("please input num: ");
    }
    while(getchar() != '\n')
        continue;
    
    return time;    
}

char get_char(void)
{
    char ch;
    
    ch = getchar();
    while(getchar() != '\n')
        continue;
    
    return ch;
}

void calculate(float time, float price)
{
    float salary_sum;
    float tax;
    float salary_taxed;
    
    if(time <= 40)
    {
        salary_sum = time * price;
    }
    else
    {
        time = 40 + (time - 40) * WORK_OVERTIME;
        salary_sum = time * price;
    }
    
    if(salary_sum <= 300)
    {
        tax = salary_sum * BASE_TAX;
    }
    else if(salary_sum > 300 && salary_sum <= 450)
    {
        tax = 300 * BASE_TAX + (salary_sum - 300) * EXTRA_TAX;
    }
    else
    {
        tax = 300 * BASE_TAX + 150 * EXTRA_TAX + (salary_sum - 450) * EXCEED_TAX;
    }
    
    salary_taxed = salary_sum - tax;
    
    printf("salary_sum: %.2f.\n", salary_sum);
    printf("tax: %.2f.\n", tax);
    printf("salary_taxed: %.2f\n\n", salary_taxed);
}

 

 

 

 

 

8、

#include <stdio.h>
float get_num(void);
char get_char(void);

int main(void)
{
    char ch;
    float num1;
    float num2;
    
    ch = get_char();
    printf("ch: %c.\n", ch);
    while(ch != 'q')
    {
        printf("enter first number: ");
        num1 = get_num();
        
        printf("num1: %.2f.\n", num1);
        printf("enter second number: ");
        
        num2 = get_num();
        while(ch == 'd' && num2 == 0)
        {
            printf("enter a number other than 0: ");
            num2 = get_num();
        }
        
        switch(ch)
        {
            case 'a': printf("%.2f + %.2f = %.2f.\n",num1, num2, num1 + num2); break;
            case 'b': printf("%.2f - %.2f = %.2f.\n", num1, num2, num1 - num2); break;
            case 'c': printf("%.2f * %.2f = %.2f.\n", num1, num2, num1 * num2); break;
            case 'd': printf("%.2f / %.2f = %.2f.\n", num1, num2, num1 / num2); break;
            default: printf("programme error.\n"); break;
        }
        while(getchar() != '\n')
            continue;
        ch = get_char();
    }
    
    return 0;
}

char get_char(void)
{
    char ch;
    printf("a). add                b). subtract\n");
    printf("c). multiply           d). devided\n");
    printf("q). quit.\n");
    printf("please input your choice: ");
    while((ch = getchar()) != 'q' && (ch < 'a' || ch > 'd'))
    {
        while(getchar() != '\n')
            continue;
        printf("you can only choose a-d and q: ");
    }
    return ch;
}


float get_num(void)
{
    float num;
    char ch;

    while(scanf("%f", &num) != 1)
    {
        while((ch = getchar()) != '\n')
            putchar(ch);
        printf(" is not num.\n");
        printf("please input again: ");
    }
    
    return num;
}

 

#include <stdio.h>
void get_memo(void);
float get_num(void);

int main(void)
{
    float first, second;
    char ch;
    
    do
    {
        get_memo();
        ch = getchar();
        
        switch(ch)
        {
            case 'a':
                printf("please input first num: "); 
                first = get_num(); 
                printf("please input second num: ");
                second = get_num(); 
                printf("%.2f + %.2f = %.2f.\n\n", first, second, first + second); 
                break;
            case 'b': 
                printf("please input first num: ");
                first = get_num(); 
                printf("please input the second num: ");
                second = get_num(); 
                printf("%.2f - %.2f = %.2f.\n\n", first, second, first - second);
                break;
            case 'c': 
                printf("please input first num: ");
                first = get_num(); 
                printf("please input scond num: ");
                second = get_num(); 
                printf("%.2f * %.2f = %.2f.\n\n", first, second, first * second);
                break;
            case 'd': 
                printf("please input first num: ");
                first = get_num(); 
                printf("please input second num: ");
                while((second = get_num()) == 0)
                {
                    printf("enter number other than 0: ");
                }
                printf("%.2f / %.2f = %.2f.\n\n", first, second, first / second);
                break;
            case 'q': break;
            default: printf("\nyou can only input a-d and q! \n"); break;
        }
            while(getchar() != '\n');
                continue; 
            putchar('\n');
    }
    while(ch != 'q');
    
    return 0;
}

void get_memo(void)
{
    printf("the options are as below: \n");
    printf("a) add              b) subtract\n");
    printf("c) multiply         d) devided\n");
    printf("q) quit\n");
    printf("please input your choice: ");
}

float get_num(void)
{
    float num;
    char ch;
    
    while(scanf("%f", &num) != 1)
    {
        while((ch = getchar()) != '\n')
            putchar(ch);
        printf(" is not num.\n");
        printf("please input num: ");
    }
    
    return num;
}