c primer plus 6编程练习

1、

#include <stdio.h>

#define NUM 26

int main(void)
{
    char letters[NUM];
    int i;
    
    for(i = 0; i < NUM; i++)
    {
        letters[i] = 'a' + i;
    }
    
    for(i = 0; i < NUM; i++)
    {
        printf("letters[%d] = %c.
", i, letters[i]);    
    } 
    
    return 0;
}

#include <stdio.h>

int main(void)
{
    const int NUM = 26;
    int i;
    char letters[NUM];
    char ch;
    
    for(ch = 'a', i = 0; i < NUM; ch += 1, i++)
    {
        letters[i] = ch;
    }
    
    for(i = 0; i < NUM; i++)
    {
        printf("letters[%d] = %c.
", i, letters[i]);
    }
    
    return 0;
}

#include <stdio.h>

int main(void)
{
    char alphabet[26];
    int i;
    char c = 'a';
    
    for(i = 0; i < 26; i++, c++)
    {
        alphabet[i] = c;
    }
    
    for(i = 0; i < 26; i++)
        printf("index[%d]: %c
",i, alphabet[i]);
    
    return 0;
}

2、

#include <stdio.h>

int main(void)
{
    int i, j;
    
    for(i = 1; i <= 5; i++)
    {
        for(j = 1; j <= i; j++)
        {
            printf("%c", '$'); 
        }
        printf("
");
    }
    
    return 0;
}

#include <stdio.h>

int main(void)
{
    int i = 1;
    
    while(i <= 5)
    {
        int j = 1;
        while(j++ <= i)
        {
            printf("%c", '$');
        }
        printf("
");
        i++;
    }
    
    return 0;
}

#include <stdio.h>

int main(void)
{
    int i = 1;
    int j;
    
    while(i <= 5)
    {
        for(j = 1; j <= i; j++)
        {
            printf("%c", '$');
        }
        printf("
");
        
        i++; 
    }
    
    return 0;
}

#include <stdio.h>

int main(void)
{
    int i = 1;
    int j;
    
    do
    {
        for (j = 1; j <= i; j++)
        {
            printf("%c", '$');
        }
        printf("
");
    }
    while(++i <= 5);
    
    return 0;
}

3、

#include <stdio.h>

int main(void)
{
    int i, j;
    
    for(i = 1; i <= 6; i++)
    {
        for(j = 1; j <= i; j++)
        {
            printf("%c", 'F' + 1 - j);
        }
        printf("
"); 
    }
    
    return 0;
}

#include <stdio.h>

int main(void)
{
    int i, j;
    char ch;
    
    for(i = 1; i <= 6; i++)
    {
        for(ch = 'F', j = 1; j <= i; ch--, j++ )
        {
            printf("%c", ch);
        }
        printf("
");
    }
    
    return 0;
}

#include <stdio.h>

int main(void)
{
    int i, j;
    char ch;
    
    for(i = 1; i <= 6; i++)
    {
        ch = 'F';
        for(j = 1; j <= i; j++)
        {
            printf("%c", ch--);
        }
        printf("
");
    }
    
    return 0;
}

4、

#include <stdio.h>

int main(void)
{
    int i, j;
    char ch;
    
    for(i = 1; i <= 6; i++)
    {
        ch = 'A' + i * (i - 1) / 2; 
        for(j =1; j <= i; j++)
        {
            printf("%c", ch++);
        }
        printf("
");
    }
    
    return 0;
}

#include <stdio.h>

int main(void)
{
    int i, j;
    char ch = 'A';
    
    for(i = 1; i <= 6; i++)
    {
        for(j = 1; j <= i; j++)
        {
            printf("%c", ch + j - 1);    
        }
        ch += j - 1;
        printf("
");
    }
    
    return 0;
}

#include <stdio.h>

int main(void)
{
    int i, j;
    char ch = 'A';
    
    for(i = 1; i <= 6; i++)
    {
        for(j = 1; j <= i; ch++, j++)
        {
                printf("%c", ch);
        }
        printf("
");
    }
    
    return 0;
}

#include <stdio.h>

int main(void)
{
    int i, j;
    char ch = 'A';
    
    for(i = 1; i <= 6; i++)
    {
        for(j = 1; j <= i; j++)
        {
            printf("%c", ch++);
        }
        printf("
"); 
    }
    
    return 0;
}

5、

#include <stdio.h>

int main(void)
{
    int i, j;
    char ch;
    int end;
    
    printf("please input an letter: ");
    scanf("%c", &ch);
    end = 26 - ('Z' - ch);
    
    for(i = 1; i <= end; i++)
    {
        for(j = 1; j <= end - i; j++)
        {
            printf(" ");
        }
        for(ch = 'A', j = 1; j <= i; ch++,j++)
        {
            printf("%c", ch);
        }
        for(ch = 'A' + i - 2, j = 1; j < i; ch--, j++)
        {
            printf("%c", ch);
        }
        printf("
");
    }
    
    return 0;
}

#include <stdio.h>

int main(void)
{
    int i, j;
    char ch;
    int end;
    
    printf("please input an letter: ");
    scanf("%c", &ch);
    end = 26 - ('Z' - ch);
    
    for(i = 1; i <= end; i++)
    {
        for(j = 1; j <= end - i; j++)
        {
            printf(" ");
        }
        for(ch = 'A', j = 1; j <= i; ch++,j++)
        {
            printf("%c", ch);
        }
        for(ch -= 2, j = 1; j < i; ch--, j++)
        {
            printf("%c", ch);
        }
        printf("
");
    }
    
    return 0;
}

#include <stdio.h>

int main(void)
{
    int i, j, end;
    char ch;
    
    printf("please input an upper letter: ");
    scanf("%c", &ch);
    
    end = ch - 'A' + 1;
    
    for(i = 1; i <= end; i++)
    {
        for(j = 1; j <= end - i; j++)
        {
            printf(" "); 
        }
        for(ch = 'A'; j <= end; j++)
        {
            printf("%c", ch++);
        }
        for(ch -= 2, j = 1; j < i; j++)
        {
            printf("%c", ch--);
        }
        printf("
");
    }
    
    return 0;
}

6、

#include <stdio.h>

int main(void)
{
    int start, stop;
    int i;
    
    printf("please input the start: ");
    scanf("%d", &start);
    
    printf("please input the stop: ");
    scanf("%d", &stop);
    
    printf("  num   square   cubic.
");
    
    for(i = start; i <= stop; i++)
    {
        printf("%5d  %5d   %5d.
", i, i * i, i * i * i);    
    }
    
    return 0;
} 

#include <stdio.h>

int main(void)
{
    int start, end;
    
    printf("please input the start number: ");
    scanf("%d", &start);
    
    printf("please input the end number: ");
    scanf("%d", &end);
    
    printf("   ori      square      cubic
");
    
    int i;
    for(i = start; i <= end; i++)
    {
        printf("%6d %10d %10d.
", i, i * i, i * i * i);
    }
    
    return 0;
}

7、

#include <stdio.h>
#include <string.h>


int main(void)
{
    char word[120];
    int len;
    int i;
    
    printf("please input an word: ");
    scanf("%s", &word);
    
    len = strlen(word);
    
    for(i = len - 1; i >= 0; i--)
    {
        printf("%c
", word[i]);
    }
    
    return 0;
    
}

#include <stdio.h>
#include <string.h>

int main(void)
{
    char word[30];
    int i;
    
    printf("please enter the words: ");
    scanf("%s", &word);
    
    i = strlen(word);
    
    for(i -= 1; i >= 0; i--)
    {
        printf("%c
", word[i]);
    }
    
    return 0;
}

8、

#include <stdio.h>

int main(void)
{
    float num1, num2;
    
    printf("please input two float number: ");
    
    while(scanf("%f %f", &num1, &num2))
    {
        printf("result: %.2f.
", (num1 - num2) / (num1 * num2));
        printf("continue to input(q to quit): ");
    }
    
    return 0;
}

9、

#include <stdio.h>

double func(double x, double y);

int main(void)
{
    double num1, num2;
    double result;
    
    printf("please input two float nums: ");
    
    while(scanf("%lf %lf", &num1, &num2) == 2)
    {
        result = func(num1, num2);
        printf("result: %.2f.
", result);
        printf("continue to enter: ");
    }
    

    
    return 0;
}

double func(double x, double y)
{
    double output;
    
    output = (x - y) / (x * y);
    
    return output;
}

10、

#include <stdio.h>

int main(void)
{
    int num1, num2;
    
    printf("please input num1: ");
    scanf("%d", &num1);
    
    printf("please input num2: ");
    scanf("%d", &num2);
    
    while(num1 < num2)
    {
        printf("the lower and upper is: %d and %d.
", num1, num2);
        int i, sum = 0;
        
        for(i = num1; i <= num2; i++)
        {
            sum += i * i;    
        }    
        printf("the sum of the square %d to %d is %d.
", num1 * num1, num2 * num2, sum);
        
        printf("please input num1: ");
        scanf("%d", &num1);
        
        printf("please input num2: ");
        scanf("%d", &num2); 
    } 
    
    return 0;
}

11、

#include <stdio.h>
#define NUM 8

int main(void)
{
    int num[NUM];
    int i;
    
    for(i = 0; i < NUM; i++)
    {
        printf("num[%d]: ", i);
        scanf("%d", &num[i]);
    }
    
    printf("-------------
");
    
    for(i = NUM - 1; i >= 0; i--)
    {
        printf("num[%d] = %d.
", i, num[i]);
    }
    
    return 0;
}

12、

#include <stdio.h>

int main(void)
{
    int length;
    double sum = 0.0;
    int i;
    
    printf("please input the length: ");
    scanf("%d", &length);
    
    while(length > 0)
    {
        sum = 0.0;
        for(i = 1; i <= length; i++)
        {
            sum = sum + 1.0/i;
        }
        
        printf("the sum for 1.0 + ... + 1.0/%d.0 is %lf
", length, sum);
        
        sum = 0.0;
        for(i = 1; i <= length; i++)
        {
            if(i % 2 == 0)
            {
                sum = sum - 1.0/i;
            }
            else
            {
                sum = sum + 1.0/i;
            }
        }
        printf("the sum of 1.0 - 1.0/2.0 + ...- 1.0/%d.0 is %lf
", length, sum);
        
        sum = 0.0;
        for(i = 1; i <= length; i++)
        {
            if(i % 2 != 0)
            {
                sum = sum + 2 * 1.0/i;
            }
        }
        printf("sum of the two sequence %d: %lf
", length, sum);
        
        printf("length(0 to quit): ");
        scanf("%d", &length);
    }
    
    return 0;
}

13、

#include <stdio.h>
#define NUM 8


int main(void)
{
    int array1[NUM];
    int i, tmp = 2;
    
    for(i = 0; i < NUM; i++)
    {
        array1[i] = tmp;    
        tmp *= 2;
    }    
    
    i = 0;
    do
    {
        printf("array1[%d] = %d.
", i, array1[i] );
        i++;
    }
    while(i < NUM);
    
    return 0;
} 

#include <stdio.h>
#define NUM 8

int main(void)
{
    int array1[NUM];
    int i;
    array1[0] = 2;
    
    for(i = 1; i < NUM; i++)
    {
        array1[i] = array1[i - 1] * 2;
    }
    
    i = 0;
    do
    {
        printf("array1[%d] = %d.
", i, array1[i]);
        i++; 
    }
    while(i < NUM);
    
    return 0;
}

14、

#include <stdio.h>
#define NUM 8


int main(void)
{
    double array1[NUM], array2[NUM];
    int i, j;
    
    for(i = 0; i < NUM; i++)
    {
        printf("array1[%d] = ", i);
        scanf("%lf", &array1[i]);
    }
    
    for(i = 0; i < NUM; i++)
    {
        for(j = 0; j <= i; j++)
        {
            array2[i] += array1[j];
        }
    }
    
    printf("array1: ");
    for(i = 0; i < NUM; i++)
    {
        printf("%5.2f ", array1[i]);
    }
    printf("
array2: ");
    for(i = 0; i < NUM; i++)
    {
        printf("%5.2f ", array2[i]);
    }
    
    return 0;
}

#include <stdio.h>
#define NUM 8

int main(void)
{
    double array1[NUM], array2[NUM];
    int i;
    
    for(i = 0; i < NUM; i++)
    {
        printf("array1[%d] = ", i);
        scanf("%lf", &array1[i]);
    }
    
    array2[0] = array1[0];
    for(i = 1; i < NUM; i++)
    {
        array2[i] = array2[i - 1] + array1[i];
    }
    
    printf("array1: ");
    for(i = 0; i < NUM; i++)
    {
        printf("%5.2f ", array1[i]);
    }
    printf("
array2: ");
    for(i = 0; i < NUM; i++)
    {
        printf("%5.2f ", array2[i]);
    }
    
    return 0;
    
}

#include <stdio.h>
#define NUM 8

int main(void)
{
    double array1[NUM], array2[NUM];
    int i, j;
    
    for(i = 0; i < NUM; i++)
    {
        printf("array1[%d]: ", i);
        scanf("%lf", &array1[i]);    
    }    
    
    
    for(i = 0; i < NUM; i++)
    {
        array2[i] = 0;
        for(j = 0; j <= i; j++)
        {
            array2[i] += array1[j];
        }
    }
    
    printf("array1: ");
    for(i = 0; i < NUM; i++)
    {
        printf("%5.2f ", array1[i]);
    }
    printf("
array2: ");
    for(i = 0; i < NUM; i++)
    {
        printf("%5.2f ", array2[i]);
    }
    
    return 0;
} 

#include <stdio.h>
#define NUM 8

int main(void)
{
    double array1[NUM], array2[NUM];
    int i;
    
    for(i = 0; i < NUM; i++)
    {
        printf("array1[%d]: ", i);
        scanf("%lf", &array1[i]);
    }
    
    
    array2[0] = array1[0];
    
    for(i = 1; i < NUM; i++)
    {
        array2[i] = array2[i - 1] + array1[i];
    }
    
    printf("array1: ");
    for(i = 0; i < NUM; i++)
    {
        printf("%5.2f ", array1[i]);
    }
    
    printf("
array2: ");
    for(i = 0; i < NUM; i++)
    {
        printf("%5.2f ", array2[i]);
    }
    
    return 0;
}

#include <stdio.h>

int main(void)
{
    double first[8], second[8];
    int i,  j;
    
    printf("enter 8 data to first array: ");
    for(i = 0; i < 8; i++)
    {
        scanf("%lf", &first[i]);
    }
    
    
    for(i = 0; i < 8; i++)
    {
        double sum = 0;
        for(j = 0; j <= i; j++)
        {
            sum = sum + first[j];
        }
        second[i] = sum;
    }
    
    printf("all the data of two array:
");
    printf("first array: ");
    for(i = 0; i < 8; i++)
    {
        printf("%12lf.", first[i]);
    }
    
    printf("
second array: ");
    for(i = 0; i < 8; i++)
    {
        printf("%12lf.", second[i]);
    }
    
    return 0;
}

15、

#include <stdio.h>
#include <string.h>

int main(void)
{
    char line[128];
    int i, len;
    
    printf("please input an string: ");
    scanf("%s", line);
    
    len = strlen(line);
    
    for(i = len - 1; i >= 0; i--)
    {
        printf("line[%d] = %c.
", i, line[i]);
    }
    
    return 0;
}

#include <stdio.h>

int main(void)
{
    char data[256];
    printf("enter the char in a line: ");
    int i = 0;
    
    do
    {
        scanf("%c", &data[i]);    
    }    
    while(data[i] != '
' && ++i);
    
    printf("the reverse char of the data: ");
    
    for(i--; i >= 0; i--)
    {
        printf("%c", data[i]);
    }
    
    printf("
done!
");
    return 0;
} 

16、

#include <stdio.h>

int main(void)
{
    double sumdap = 100.0, sumdei = 100.0;
    int i;
    
    for(i = 0; sumdap >= sumdei; i++)
    {
        sumdap += 100 * 0.1;
        sumdei += sumdei * 0.05;
    }
    
    printf("year:  %d.
", i);
    printf("sumdap: %.2f
", sumdap);
    printf("sumdei: %.2f
", sumdei);
    
    return 0;
}

#include <stdio.h>

int main(void)
{
    double sumdap = 100.0, sumdei = 100.0;
    int i = 0;
    
    while(sumdap >= sumdei)
    {
        sumdap += 100 * 0.1;
        sumdei += sumdei * 0.05;
        i++;
    }
    
    printf("year:  %d.
", i);
    printf("sumdap: %.2f
", sumdap);
    printf("sumdei: %.2f
", sumdei);
    
    return 0;
}

#include <stdio.h>

int main(void)
{
    double sumdap = 100.0, sumdei = 100.0;
    int i = 0;
    
    do
    {
        sumdap += 100.0 * 0.1;
        sumdei += sumdei * 0.05;
        i++; 
    }
    while(sumdei < sumdap);
    
    printf("year: %d.
", i);
    printf("sumdei: %.2f
", sumdei);
    printf("sumdap: %.2f
", sumdap);
    
    return 0;
}

#include <stdio.h>

int main(void)
{
    float daphne, deirdre;
    daphne = deirdre = 100.0;
    int year = 0;
    
    do
    {
        daphne = daphne + 100 * 0.1;
        deirdre = deirdre + deirdre * 0.05;
        year++;
    }
    while((deirdre - daphne) < 0);
    
    printf("%d years later. 
 daphne = %f.
deirdre = %f.
", year, daphne, deirdre);
    
    return 0;
}

17、

#include <stdio.h>

int main(void)
{
    double sumchu = 100;
    int i;
    
    for(i = 0; sumchu > 0; i++)
    {
        sumchu += (sumchu * 0.08) - 10;
    }
    
    printf("year: %d.
", i);
    printf("sumchu: %f.
", sumchu);
    
    return 0;
    
}

#include <stdio.h>

int main(void)
{
    double sumchu = 100;
    int i = 0;
    
    do
    {
        sumchu += sumchu * 0.08 - 10;
        i++;
    }
    while(sumchu > 0);
    
    printf("year: %d.
", i);
    printf("sumchu: %f
", sumchu);
    
    return 0;
}

18、

#include <stdio.h>

int main(void)
{
    int a = 5;
    int i;
    
    for(i = 1; a < 150 ; i++)
    {
        a = (a - i) * 2;
        printf("%d week sum: %d.
",i, a);
    }
    
    return 0;
}

#include <stdio.h>

int main(void)
{
    int rabnud = 5;
    int weeks = 1;
    
    while(rabnud < 150)
    {
        printf("at %d weeks, firend: %d.
", weeks, rabnud);
        rabnud = 2 * (rabnud - weeks++);
    }
    
    return 0;
}