学步园

3.

#include <stdio.h>
int main (void)
{
    int i = 1;
    float n;
    printf("Watch out! Here come a bunch of fractions!\n");
    while(i++ < 30) {
        n = 1.0/i;//将1改为1.0，当2个数都是整数时，第一次结果为1，当I增大时结果会一直为0，改为1.0（浮点型）则会有不同结果
        printf("%f\n",n);
    }
    printf("That`s all,folks!\r");
    return 0;
}

4.

#include <stdio.h>
#define FORMAT "%s! C is cool!\n"
int main (void)
{
    int num = 10;
    printf(FORMAT, FORMAT);
    printf("%d\n", ++num);
    printf("%d\n", num++);
    printf("%d\n", num--);
    printf("%d\n", num);
    return 0;
}

结果

%s! C is cool!
! C is cool!
11
11
12
11

6.

#include <stdio.h>
int main (void)
{
    char c1,c2;
    int diff;
    float num;

    c1 = 'S';
    c2 = 'O';
    diff = c1 - c2;
    num = diff;
    printf("%c%c%c: %d %3.2f\n", c1, c2,c1,diff,num);
    return 0;
}

打印结果

SOS: 4 4.00

7.

#include <stdio.h>
#define TEN 10
int main (void)
{
    int n = 0;
    while(n++ < TEN)
        printf("%5d",n);
    printf("\n");
    return 0;
}

8.

#include <stdio.h>
int main (void)
{
    char c = 'a';
    while(c <= 'g')
        printf("%5c",c++);
    printf("\n");
    return 0;
}

9.

a.

   1   2 

b.

   101

   102

   103

   103

c.

stuvw

编程练习

1.

#include <stdio.h>
int main (void)
{
    const int MAX = 60;
    int num;
    while(num > 0) {
        scanf("%d",&num);
    }
    return 0;
}

2.

#include <stdio.h>
int main (void)
{
    int pl = 10;
    int num;
    printf("请输入数字\n");
    scanf("%d",&num);
    while(pl >= 0) {
        printf("%d\n",num+pl);
        pl--;
    }
    return 0;
}

3.

#include <stdio.h>
int main (void)
{
    const int PW = 7;
    int days;
    printf("请输入天数\n");
    scanf("%d",&days);
    printf("%d周%d天",days/PW,days%PW);
    return 0;
}

4.

#include <stdio.h>
int main (void)
{
    const float I_T_M = 2.54;
    const float M_T_I = 0.3937;
    float cm;
    while(cm > 0) {
        printf("请输入厘米长度\n");
        scanf("%f",&cm);
        printf("%.2fcm\n%.2finch\n",cm,cm*I_T_M);
    }
    return 0;
}

5.

#include <stdio.h>
int main (void)
{
    int count,sum,days;
    count = 0;
    sum = 0;
    scanf("%d",&days);
    while(count++ < days)
        sum = sum + count;
    printf("sum = %d\n", sum);
    return 0;
}

6.

#include <stdio.h>
int main (void)
{
    int count,sum,days;
    count = 0;
    sum = 0;
    scanf("%d",&days);
    while(count++ < days)
        sum = sum + count * count;
    printf("sum = %d\n", sum);
    return 0;
}

7.

#include <stdio.h>
int main (void)
{
    float num;
    scanf("%f",&num);
    printf("%f", num * num * num);
    return 0;
}

8.

#include <stdio.h>
//用到atof函数需要此包
#include <stdlib.h>
int main (void)
{
    char fahrenheit[40];
    double params;
    int n;
    while(1)
    {
        printf("请输入华氏温度\n");
        scanf("%s",fahrenheit);
        n = strlen(fahrenheit);
        int i = 0;
        for(i=0; i<n; i++)
        {
            if((fahrenheit[i] < '0' || fahrenheit[i] > '9') && fahrenheit[i] != '.')
            {
                return 0;
            }
        }
        temperatures(atof(fahrenheit));
    }
    return 0;
}

void temperatures(double fahrenheit)
{
    const float C1 = 1.8;
    const float C2 = 32.0;
    const float K = 273.16;
    double celsius,kelvin;
    celsius = C1 * fahrenheit + C2;
    kelvin = celsius * K;
    printf("摄氏%f度\n",celsius);
    printf("绝对温度%f度\n",kelvin);
}