c primer plus(五版)編程練習-第七章編程練習

1．編寫一個程式。該程式讀取輸入直到遇到#字元，然後報告讀取的空格數目、讀取的換行符數目以及讀取的所有其他字元數目。 2．編寫一個程式。該程式讀取輸入直到遇到#字元。使程式列印每個輸入的字元以及它的十進位ASCII 碼。每行列印8 個字元/編碼對。建議：利用字元計數和模運算符(%)在每8 個迴圈周期 ...

1．編寫一個程式。該程式讀取輸入直到遇到#字元，然後報告讀取的空格數目、讀取的換行符數目以及讀取的所有其他字元數目。

#include<stdio.h>
#include<ctype.h>
int main(void){
    char ch;
    int count1,count2,count3;
    count1 = count2 = count3 = 0;
 　　printf("Enter text to be analyzed(#to terminate)：\n");
    while((ch = getchar()) != '#'){
        if ( ch == '\n'){
            count1++;
        } else if(isspace(ch)){
            count2++;
        } else if (!isspace(ch)){
            count3++;
        }
    }
    printf("換行數量%d,空格數量%d,其他字元數量%d",count1,count2,count3);
    return 0;
}

2．編寫一個程式。該程式讀取輸入直到遇到#字元。使程式列印每個輸入的字元以及它的十進位ASCII 碼。每行列印8 個字元/編碼對。建議：利用字元計數和模運算符(%)在每8 個迴圈周期時列印一個換行符。

#include<stdio.h>
#define STOP '#'
int main(void){
    char ch;
    int length = 1;
    printf("Enter text to be analyzed(#to terminate)：\n");
    while((ch = getchar()) != STOP){
        if(length%8==0){
            printf("\n");
        }
        printf("%c/%d ",ch,ch);
        length++;
    }
    return 0;
}

3．編寫一個程式。該程式讀取整數，直到輸入0。輸入終止後，程式應該報告輸入的偶數(不包括0)總個數、偶數的平均值，輸入的奇數總個數以及奇數的平均值。

#include<stdio.h>
int main(void){
    int num,even_num,odd_num;
    double even_count,odd_count;//必需定義為double類型,否則列印平均值會出錯
    even_num = odd_num = 0;
    even_count = odd_count = 0.0 ;
    printf("Enter int to be analyzed(0 to terminate)：\n");
    while (scanf("%d", &num) == 1 && num != 0){
            if (num%2 == 0){
                even_num++;
                even_count +=num;
            } else {
                odd_num++;
                odd_count +=num;
            }
    }
    if (even_count > 0)
        printf("Even have %d, even average is %.2f\n",even_num,even_count / even_num);
    if (odd_num > 0)
        printf("Odd have %d,odd average is %.2f",odd_num,odd_count/odd_num);
    return 0;
}

4．利用if else 語句編寫程式讀取輸入，直到#。用一個感嘆號代替每個句號，將原有的每個感嘆號用兩個感嘆號代替，最後報告進行了多少次替代。

#include<stdio.h>
#define STOP '#'
int main(void){
    char ch;
    int i;
    i = 0;
    while((ch = getchar()) != STOP){
        if (ch == '.'){
            putchar('!');
            i++;
        } else if (ch == '!'){
            putchar(ch);
            putchar(ch);
            i++;
        } else {
            putchar(ch);
        }
    }
    printf("\n");
    printf("count %d",i);
    return 0;
}

5．用switch 重做練習3。

#include<stdio.h>
int main(void){
    int num,even_num,odd_num;
    double even_count,odd_count;//必需定義為double類型,否則列印平均值會出錯
    even_num = odd_num = 0;
    even_count = odd_count = 0.0 ;
    printf("Enter int to be analyzed(0 to terminate)：\n");
    while (scanf("%d", &num) == 1 && num != 0){
            switch (num%2){
                case 0:
                    even_num++;
                    even_count +=num;
                    break;
                case 1:
                    odd_num++;
                    odd_count +=num;
                    break;
            }
    }
    if (even_count > 0)
        printf("Even have %d, even average is %.2f\n",even_num,even_count / even_num);
    if (odd_num > 0)
        printf("Odd have %d,odd average is %.2f",odd_num,odd_count/odd_num);
    return 0;
}

6．編寫一個程式讀取輸入，直到#，並報告序列ei 出現的次數。說明此程式必須要記住前一個字元和當前的字元。用諸如“Receive your eieio award.”的輸入測試它。

#include<stdio.h>
#define STOP '#'
#define PREV_CHAR 'e'
#define CURRENT_CHAR 'i'
int main(void){
    char ch, prev_char;
    int i;
    i = 0;
    prev_char = 0;
    printf("Enter text to be analyzed(#to terminate)：\n");
    while((ch = getchar()) != STOP){
        if (ch == PREV_CHAR){
            prev_char = ch;
        }
        if (ch == CURRENT_CHAR && prev_char == PREV_CHAR){
            i++;
        }
    }
    printf("Enter of 'ei' %d ",i);
    return 0;
}

7．編寫程式，要求輸入一周中的工作小時數，然後列印工資總額、稅金以及凈工資。作如下假設：
a．基本工資等級=10.00 美元/小時
b．加班(超過40 小時)=1.5 倍的時間
c．稅率前300 美元為15%
下一個150 美元為20%餘下的為25%。

用#define 定義常量，不必關心本例是否符合當前的稅法。

#include<stdio.h>
#define BASE 10.00
#define TAX_LEVEL1 300
#define TAX_LEVEL2 150
#define TAX_LEVEL1_RATE 0.15
#define TAX_LEVEL2_RATE 0.2
#define TAX_LEVEL3_RATE 0.25
#define BASE_HOUR 40
#define OVER_RATE 1.5
int main(void){
    float num,wage,tax,real_wage,temp,real_hour;
    wage = tax = real_wage = real_hour = 0.0;
    printf("Please enter the number of hours you work a week：\n");
    scanf("%f",&num);

    if (num > BASE_HOUR){
        real_hour = num + (num - BASE_HOUR)*OVER_RATE;
    } else {
        real_hour = num;
    }
    wage = real_hour*BASE;
    temp = wage - TAX_LEVEL1;
    if (temp <= 0){
        tax += wage*TAX_LEVEL1_RATE;
    } else {
        tax +=TAX_LEVEL1*TAX_LEVEL1_RATE;
        if (temp<= TAX_LEVEL2){
            tax += temp*TAX_LEVEL2_RATE;
        } else {
            tax += TAX_LEVEL2*TAX_LEVEL2_RATE;
            tax += (temp - TAX_LEVEL2) * TAX_LEVEL3_RATE;
        }
    }
    real_wage = wage - tax;
    printf("hour:%.2f wage:%.2f tax:%.2f real wage :%.2f",num,real_hour,wage,tax,real_wage);
    return 0;
}

8．修改練習7 中的假設a，使程式提供一個選擇工資等級的菜單。用switch 選擇工資等級。程式運行的開頭應該像這樣：
*****************************************************************
Enter the number corresponding to the desired pay rate or action：
1)$8.75/hr 2)$9.33/hr
3)$10.00/hr 4)$11.20/hr
5)quit
*****************************************************************

如果選擇1 到4，那麼程式應該請求輸入工作小時數。程式應該一直迴圈運行，直到輸入5。如果輸入1 到5 以外的選項，那麼程式應該提醒用戶合適的選項是哪些，然後再迴圈。用#define 為各種工資等級和稅率定義常量。

#include<stdio.h>
#define LEVEL1 8.75
#define LEVEL2 9.33
#define LEVEL3 10.00
#define LEVEL4 11.20
#define TAX_LEVEL1 300
#define TAX_LEVEL2 150
#define TAX_LEVEL1_RATE 0.15
#define TAX_LEVEL2_RATE 0.2
#define TAX_LEVEL3_RATE 0.25
#define BASE_HOUR 40
#define OVER_RATE 1.5
int main(void){
    int level;
    float fee,num,wage,tax,real_wage,temp,real_hour;
    wage = tax = real_wage = real_hour = fee = 0.0;

    printf("*****************************************************************\n");
    printf("Enter the number corresponding to the desired pay rate or action：\n");
    printf("1)$8.75/hr    2)$9.33/hr\n");
    printf("3)$10.00/hr   4)$11.20/hr\n");
    printf("5)quit\n");
    printf("*****************************************************************\n");
    while(scanf("%d",&level) == 1 && level != 5){

      switch(level){
        case 1:
            fee = LEVEL1;
            break;
        case 2:
            fee = LEVEL2;
            break;
        case 3:
            fee = LEVEL3;
            break;
        case 4:
            fee = LEVEL4;
            break;
        default:
             printf("You should enter the number between 1 to  4 (5 to quit).\n");
             printf("Please enter the right number: \n");
             continue;
        }
        printf("Please enter the number of hours you work a week：\n");
        scanf("%f",&num);
        if (num > BASE_HOUR){
            real_hour = num + (num - BASE_HOUR)*OVER_RATE;
        } else {
            real_hour = num;
        }
        wage = real_hour*fee;
        temp = wage - TAX_LEVEL1;
        if (temp <= 0){
            tax += wage*TAX_LEVEL1_RATE;
        } else {
            tax +=TAX_LEVEL1*TAX_LEVEL1_RATE;
            if (temp<= TAX_LEVEL2){
                tax += temp*TAX_LEVEL2_RATE;
            } else {
                tax += TAX_LEVEL2*TAX_LEVEL2_RATE;
                tax += (temp - TAX_LEVEL2) * TAX_LEVEL3_RATE;
            }
        }
        real_wage = wage - tax;
        printf("hour:%.2f wage:%.2f tax:%.2f real wage :%.2f\n",real_hour,wage,tax,real_wage);
        printf("Please enter next number:\n");
    }
    printf("exit!");
    return 0;
}

沒有學透getchar和scanf的區別，一開始用getchar獲取輸入，結果出錯了。這也告訴自己，對學習要有敬畏之心，看都教材不是看小說，要瞭解的是細節不是大概，馬虎不得。

9．編寫一個程式，接受一個整數輸入，然後顯示所有小於或等於該數的素數。

#include<stdio.h>
#include<stdbool.h>
int main(void){
    int num,i,k;
    bool isPrime;
    printf("Enter int number:\n");
    scanf("%d",&num);

    for(i=2;i<=num;i++){
        for(k=2,isPrime = true;(k*k)<=i;k++){
            if (i%k==0){

                 isPrime = false;
            }
        }
        if (isPrime){
            printf("%lu ",i);
        }
    }
    return 0;
}

10．1988 年United States Federal Tax Schedule 是近期最基本的。它分為4 類，每類有兩個等級。下麵是其摘要；美元數為應徵稅的收入。

種類	稅金
單身	前17，850 美元按15%，超出部分按28%
戶主	前23，900 美元按15%，超出部分按28%
已婚，共有	前29，750 美元按15%，超出部分按28%
已婚，離異	前14，875 美元按15%，超出部分按28%

例如，有20 000 美元應徵稅收入的單身雇佣勞動者應繳稅金0.15×17 850 美元+0.28×(20 000美元–17 850 美元)。編寫一個程式，讓用戶指定稅金種類和應徵稅收入，然後計算稅金。使用迴圈以便用戶可以多次輸入。

#include<stdio.h>
#define TYPE1 1
#define TYPE2 2
#define TYPE3 3
#define TYPE4 4
#define TAX_RATE1 0.15
#define TAX_RATE2 0.28
#define TYPE1_BASE 17850
#define TYPE2_BASE 23900
#define TYPE3_BASE 29750
#define TYPE4_BASE 14875
int main(void){
    double tax,income,base;
    int type;
    printf("請選擇稅金種類:\n");
    printf("1)單身   2)戶主  3)已婚，共有 4)已婚，離異 5)退出\n");
    while(scanf("%d",&type) == 1 && type != 5){
        switch(type){
        case TYPE1:
            base = TYPE1_BASE;
            break;
        case TYPE2:
            base = TYPE2_BASE;
            break;
        case TYPE3:
            base = TYPE3_BASE;
            break;
        case TYPE4:
            base = TYPE4_BASE;
            break;
        default:
            printf("請輸入1到4之間的數字，或者輸入5為退出\n");
            continue;
        }
        printf("請輸入您的應徵稅收入：\n");
        scanf("%lf",&income);
        if(income>base){
            tax = base*TAX_RATE1+(income-base)*TAX_RATE2;
        } else {
            tax = income*TAX_RATE1;
        }
        printf("您共要繳納%.2lf美元稅金\n",tax);
        printf("請輸入您稅金種類代碼：\n");
    }
    printf("Exit.");
    return 0;
}

感覺和第七、八題一樣，而且更沒有難度。

11．ABC Mail Order Grocery 北韓薊的售價是1.25 美元/磅，甜菜的售價是0.65 美元/磅，胡蘿蔔的售價是0.89 美元/磅。在添加運輸費用之前，他們為100 美元的訂單提供5%的打折優惠。對5磅或以下的定單收取3.50 美元的運輸和裝卸費用；超過5 磅而不足20 磅的定單收取10.00 美元的運輸和裝卸費用；20 磅或以上的運輸，在8 美元基礎上每磅加收0.1 美元。編寫程式，在迴圈中使用switch 語句，以便對輸入a 的響應是讓用戶輸入所需的北韓薊磅數，b 為甜菜的磅數，c 為胡蘿蔔的磅數，而q 允許用戶退出訂購過程。然後程式計算總費用、折扣和運輸費用(如果有運輸費的話)，以及總數。隨後程式應該顯示所有的購買信息：每磅的費用、訂購的磅數、該訂單每種蔬菜的費用、訂單的總費用、折扣，如果有的話加上運輸費用，以及所有費用的總數。

#include<stdio.h>
#define ARTICHOKE 'a'
#define BEET 'b'
#define CARROT 'c'
#define ARTICHOKE_PRICE 1.25
#define BEET_PRICE 0.65
#define CARROT_PRICE 0.89
#define SHIP_FEE_LEVEL1 3.5
#define SHIP_FEE_LEVEL2 10.00
#define SHIP_FEE_LEVEL3 0.1
#define SHIP_FEE_LEVEL3_BASE 8.0
#define WEIGHT_LEVEL1 5
#define WEIGHT_LEVEL2 20
#define DISCOUNT 0.05
#define DISCOUNT_BASE 100
int main(void){
    double fee_count,ship_fee,price,order_count,discount_count,
    pound_count,pound,artichoke_pound,beet_pound,carrot_pound,artichoke_fee,beet_fee,carrot_fee;
    char type;
    pound_count = discount_count = fee_count = ship_fee = order_count = artichoke_pound = beet_pound = carrot_pound = 0.0;
    artichoke_fee = beet_fee = carrot_fee = 0.0;
    printf("請選擇要訂購的蔬菜:\n");
    printf("a)北韓薊   b)甜菜  c)胡蘿蔔 q)退出\n");
    while(scanf("%c",&type) == 1 && type != 'q'){
        if( type != ARTICHOKE && type != BEET && type != CARROT ){
            printf("請選擇輸入a到c之間的字母，或者輸入q退出:\n");
            continue;
        }
        printf("您輸入你要訂購的磅數：");
        scanf("%lf",&pound);
        pound_count += pound;
        switch(type){
        case ARTICHOKE:
            artichoke_pound = pound;
            artichoke_fee = pound*ARTICHOKE_PRICE;
            break;
        case BEET:
            beet_pound = pound;
            beet_fee = pound*BEET_PRICE;
            break;
        case CARROT:
            carrot_pound = pound;
            carrot_fee = pound*CARROT_PRICE;
            break;
        }

    }
    if (pound_count <= WEIGHT_LEVEL1){
        ship_fee = SHIP_FEE_LEVEL1;
    } else if(pound_count > WEIGHT_LEVEL1 && pound_count < WEIGHT_LEVEL2){
        ship_fee = SHIP_FEE_LEVEL2;
    } else {
        ship_fee = SHIP_FEE_LEVEL3_BASE+ (pound_count*0.1);
    }

    fee_count = ship_fee+artichoke_fee+beet_fee+carrot_fee;
    if (fee_count>DISCOUNT_BASE){
        discount_count = DISCOUNT_BASE*DISCOUNT;
    }
    order_count = fee_count-discount_count+ship_fee;

    printf("你共訂購了%.2f磅蔬菜，平均每磅%.2f美元 \n",pound_count,order_count/pound_count);
    if (artichoke_fee>0){
        printf("訂購了北韓薊%.2f磅 共%.2f美元\n",artichoke_pound,artichoke_fee);
    }
    if (beet_fee>0){
        printf("訂購了甜菜%.2f磅 共%.2f美元\n",beet_pound,beet_fee);
    }
    if (carrot_fee>0){
        printf("訂購了胡蘿蔔%.2f磅 共%.2f美元\n",carrot_pound,carrot_fee);
    }
    printf("共%.2f美元 折扣優惠%.2f \n",fee_count,discount_count);
    if (ship_fee>0){
        printf("運費共%.2f \n",ship_fee);
    }

    printf("訂單金額%.2f\n",order_count);
    return 0;
}