"C Programming (fifth edition)" edited by Hao strong - Exercises - Chapter V

3.

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

int main()
{
    int a, b, temp, i, j, maxDivisor, minMultiple;
    printf("请输入两个正整数\n");
    scanf("%d %d", &a,&b);
    //把较小的数保存在a
    if(a > b){
        temp = a;
        a = b;
        b = temp;
    }
    //最大公约数
    for (i = a; i > 1; i--){
        if((a%i == 0)&&(b%i == 0)){
            maxDivisor = i;
            break;
        }
    }
    //最小公倍数
    for(j = b; j < a*b; j++){
        if((j%a == 0)&&(j%b == 0)){
            minMultiple = j;
            break;
        }
    }
    printf("最大公约数为: %d\n", maxDivisor);
    printf("最小公倍数为: %d\n", minMultiple);
    return 0;
}

4.

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

int main()
{
    char ch;
    int letter,space,number,other;
    letter=space=number=other=0;
    printf("请输入一行字符:\n");
    while((ch=getchar()) != '\n'){
        if((ch>='A'&& ch<='Z')||(ch>='a'&&ch<='z')){
            //字母
            letter++;
        } else if (ch == ' '){
            space++;
        } else if(ch>='0'&& ch<='9'){
            number ++;
        } else {
            other ++;
        }
    }
    printf("英文字母个数为:%d\n", letter);
    printf("空格个数为:%d\n", space);
    printf("数字个数为:%d\n", number);
    printf("其他字符个数为:%d\n", other);
    return 0;
}

5.

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

int main()
{
    int a,n,Sn=0,Tn=0,i=1;
    printf("请输入a,n的值:\n");
    scanf("%d %d", &a, &n);
    while(i<=n){
        Tn = Tn+a;
        Sn = Sn+Tn;
        a = a*10;
        i++;
    }
    printf("Sn= %d", Sn);
    return 0;
}

6.

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

int main()
{
    int n, i;
    double  eachResult = 1, result = 0;
    printf("请输入n的值: \n");
    scanf("%d", &n);
    for(i = 1; i <= n; i++){
        eachResult = eachResult * i;
        result += eachResult;
    }
    printf("阶乘和为：%f", result);
    return 0;
}

7.

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

int main()
{
    int i,j;
    double k,result = 0;
    for(i = 1; i <= 100; i++){
        result += i;
    }
    for(j = 1; j <= 50; j++){
        result += j*j;
    }
    for(k = 1; k <= 10; k++){
        result += 1/k;
    }
    printf("%f", result);
    return 0;
}

Note: If the program will set the value of k is of type int error occurs

8.

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

int main()
{

    int i, firstP, secondP, lastP;
    for ( i = 100; i < 1000; i++)
    {
        firstP = i/100;
        secondP = (i%100)/10;
        lastP = i%10;
        if ((firstP*firstP*firstP + secondP*secondP*secondP + lastP*lastP*lastP)==i)
        {

            printf("%d\n",i);
        }
    }
    return 0;
}

9.

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

int main()
{
    int i, j, k, factor;
    for(i = 1; i < 1000; i++){
        factor = 0;
        for(j = 1; j <= i/2; j++){
            if(i%j == 0){
                factor += j;
            }
        }
        if(factor == i){
            printf("%d its factors are ", i);
            for(k = 1; k <= i/2; k++){
                if(i%k == 0){
                    printf(" %d ",k);
                }
            }
            printf("\n");
        }


    }

    printf("Hello world!\n");
    return 0;
}

10.

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

int main()
{
    double molecule,denominator,sum,temp;
    int i;
    molecule=2;
    denominator=1;
    sum = molecule/denominator;
    for(i = 1; i < 20; i++){
        temp = molecule;
        molecule +=denominator;
        denominator = temp;
        sum += molecule/denominator;
    }
    printf("前20项的和为 %f\n",sum);
    return 0;
}

11.

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

int main()
{
    int i;
    double height = 100, distance = 0;
    for(i = 1; i <= 10; i++ ){
        distance += height;
        height /= 2;
        distance += height;
    }

    printf("第十次落地时共经过 %f米 \n", distance-height);
    printf("第十次落地时弹起的高度为 %f米 \n", height);
    return 0;
}

12.

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

int main()
{
    int i,sum = 1;
    for(i = 9; i >= 1; i--){
        sum = (sum+1)*2;
    }


    printf("总共有%d个桃子\n", sum);
    return 0;
}

13.

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

int main()
{
    double a,x1,x2;
    printf("请输入a的值\n");
    scanf("%lf", &a);
    x1 = a/2;
    x2 = (x1+a/x1)/2;

    do{
        x1 = x2;
        x2 = (x1+a/x1)/2;
    } while(fabs(x1-x2)>=1e-5);
    printf("平方根为%f",x2);

    return 0;
}

14

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

int main()
{
    double x1,x2,fx, fdx;
    x1 = 1.5;
    do{
        x1 = x2;
        fx = 2*pow(x1,3)-4*pow(x1,2)+3*x1-6;
        fdx = 6*pow(x1,2)-8*x1+3;
        x2 = x1 -fx/fdx;
    }while(fabs(x2-x1)>=1e-5);
    printf("根为%f", x2);
    return 0;
}

15.

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

int main()
{
    double x1,x2,x0,fx1,fx2,fx0;
    x1=-10,x2=10;
    fx1 = 2*pow(x1,3)-4*pow(x1,2)+3*x1-6;
    fx2 = 2*pow(x2,3)-4*pow(x2,2)+3*x2-6;
    do{
        x0 = (x1+x2)/2;
        fx0 = 2*pow(x0,3)-4*pow(x0,2)+3*x0-6;
        if (fx0*fx1 < 0){
            x2 = x0;
            fx2 = fx0;
        } else if (fx0*fx2 < 0){
            x1 = x0;
            fx1 = fx0;
        }
    }while(fabs(fx0)>= 1e-5);
    printf("x = %f",x0);
    return 0;
}

17.

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

int main()
{
    char i,j,k;
    for(i='X';i<='Z';i++){
        for(j='X';j<='Z';j++){
            if(i!=j){
                for(k='X';k<='Z';k++){
                    if(i!=k&&j!=k){
                        if(i!='X'&&k!='X'&&k!='Z'){
                            printf("A--%c\nB--%c\nC--%c\n",i,j,k);
                        }
                    }
                }
            }
        }
    }
    return 0;
}