【学习ios之路:C语言】循环方面试题

1.打印出如下所示图形  :

 *

*  *

* * *

代码如下:

    for (int i = 0; i < 3; i++) {
    
        for (int j = 2; j > i; j--) {
            printf(" ");
        }
       for (int k = 0; k < i + 1; k++) {
            printf(" *");
        }
        printf("\n");
        
    }

   *

 *   *

*  *  *

 *   *

   *

代码如下:

    for (int i = 0; i < 5; i++) {
        
        if (i < 3) {
             //前三行,即先打印出图形上半部分
            for (int j = 0; j < 2- i; j++) {
                printf(" ");
            }
            for (int  k = 0 ; k < i + 1 ; k++) { 
                printf("* ");
            }
            printf("\n");
        } else {
            
           //后两行,图形下半部分
            for (int j = 0; j < i-2; j++) {
                printf(" ");
            }
            for (int k = 0; k < 5- i; k++) {
                printf("* ");
            }
            printf("\n");
        }
     
    }
     

3.从控制台输入一个整数,判断是否是质数.

  
   <span style="font-size:14px;">  int n = 0, m = 0;
    printf("please input a int number:\n");
    scanf("%d", &n);
    for (m = 2; m < n ; m++) {
        if (n % m == 0  ){
            printf("不是质数:%d",n);
            break;//结束本层循环,循环结束.
        }
    }//循环结束后.
    if (m == n) {
        printf("是质数\n");
    }</span>

c语言中如何取出随机数:

    随机公式:[a,b]范围在a-b之间的随机数
    int n3 = arc4random() % ( b - a + 1) + a;

4.随机产生 20 个[10    ,    100]的正整数，输出这些数以及他们中的最大数

 <span style="font-size:14px;">int max = 0;int temp = 0;
    for (int j =0; j < 20; j++) {
        temp = arc4random() % 91 +10;
        
        if( max < temp){
            max = temp;
        }
        
    }
    printf("the max  is %d\n", max);</span>
    

 <span style="font-size:14px;">   int x = 0;//百位数
    int y = 0;//十位数
    int z = 0;//个位数
    for (int num = 100; num <= 999; num++) {
        x = num / 100;
        y = num / 10 % 10;
        z = num % 10 ;
        if (num == (x*x*x + y*y*y + z*z*z)) {
            printf("水仙花数为:%d\n",num);
        }
    }</span>

<span style="font-size:14px;">    int a = 0;
    int b = 0;
    int yushu = 0;
    printf("please intput two numbers :\n");
    scanf("%d%d", &a, &b);
    
    //辗转相除法
    int max = 0, min = 0;
    max = a > b ? a : b;//判断ab大小,把大的值给max.最为被除数
    min = a > b ? b : a;//最为除数.
    yushu = max % min;
    while (yushu != 0) {
        max = min ;
        min = yushu;
        yushu = max % min ;
    }
    printf("最大公约数为:%d\n", min);
    printf("最大公倍数为:%d\n", (a * b) / min);

   //普通方法
    for (int i = 1; i <= min; i++) {
        if (max % i == 0 && min % i == 0) {
            yue=i;
        }
    }
    printf("最大公约数为:%d\n", yue);
    printf("最小公约数:%d\n",(a*b)/yue);
</span>

<span style="font-size:14px;">    int min = 0, temp = 0, n =0;
    printf("please intput a number N:\n");
    scanf("%d", &n);
    for (int j = 0; j < n; j++) {
        temp = arc4random() % (15 - 10 + 1) + 10;
        if (j == 0) {
            min = temp;
        } else if( min > temp){
            min = temp;
        }
    }
    printf("the min is %d\n", min);</span>