循环

勇者愤怒，抽刃向更强者；怯者愤怒，却抽刃向更弱者。 ———鲁迅

• 1.循环打印1-100的数字

int i = 1;// 初始化
    while(i < = 100){// 条件表达式
        printf("%d\t",i);// 循环体
        i++;// 增量
    }

• 2.0-250的摄氏度和华氏度的对照表

int i = 0,count = 1;
    printf("编号\t摄氏度\t华氏度\n");
    while(i < = 250 && count < = 10){
        printf("%d\t%d\t%.2lf\n",count,i,i*9/5.0+32);
        i + = 20;
        count++;
    }

• 3.求1-1000的水仙花数

int i = 100;
    while(i < = 999){
        int g = i/1%10;
        int s = i/10%10;
        int b = i/100%10;
        if(g*g*g+s*s*s+b*b*b == i){
            printf("%d\t",i);
        }
        i++;
    }

• 4.打印一个正方形

int i = 1;
    while(i < = 10){
        int j = 1;
        while(j < = i){
            printf("* ");
            j++;
        }
        printf("\n");
        i++;
    }

• 5.判断输入多少字符并选择是否继续

char c,a;
    do{
        printf("请输入一些字符:\n");
        fflush(stdin);
        int i = 0;
        do{
            c = getchar();
            i++;
        }while(c != '\n');
        printf("你输入了%d个字符\n",--i);
        printf("是否继续:y/n\n");
        a = getchar();
    }while(a == 'y' || a == 'Y');

• 6.输入一个数，判断是否合法，如合法将其反转

int i;
    do{
        printf("请输入一个数:\n");
        scanf("%d",&i);
        if(i < = 0){
            printf("输入的数不合法\n");
        }
    }while(i < = 0);
    // 反转
    double sum = 0;
    double k = 1.0;
    int h = 1;
    do{
        int g = i/1%10;
        k = k/10;
        sum += double(g)*k;
        h* = 10;
        i = i/10;
    }while(i != 0);
    double d = sum*h;//321.00000
    printf("反转后的数是:%d\n",int(d));

• 7.斐波那契数列

int i,j,sum;
    i = 2 ; j = 2 ; sum = j;
    for(int k = 3;k < = 20;k++){
        sum = i+j;
        i = j;
        j = sum;
        printf("第%d个月有%d只\n",k,sum);
    }

• 8.打印等腰三角形

        int row;
            printf("请输入要打印的等腰三角形行数：");
            scanf("%d",&row);
            for(int i = 0 ; i < row ; i++) {
                 for(int j = 0;j < row-i-1 ;j++){
                 printf(" ");
                                      }
                        for (int K = 0; K < 2*i+1;K++) {
                        printf("*");
                               }
            printf("\n");
            }

• 9.输入日期，判断是一年的第几天

int n,y,r,s;
    int e = 28;
    printf("请输入日期：(2018-3-15)\t");
    scanf("%d-%d-%d",&n,&y,&r);
    if(n%4 == 0&& n%100 != 0|| n%400 == 0)
    { e = 29;}
    switch(1){
    case 1 :
        s = r;
        if(y == 1){
            break;
        }
        case 2 :
            s += 31;
            if(y == 2){
            break;
            }
        case 3 :
            s += e;
            if(y == 3){
            break;
            }
            case 4 :
            s += 31;
            if(y == 4){
            break;
            }
            case 5 :
            s += 30;
            if(y == 5){
            break;
            }
            case 6 :
            s += 31;
            if(y == 6){
            break;
            }
            case 7 :
            s += 30;
            if(y == 7){
            break;
            }
            case 8 :
            s += 31;
            if(y == 8){
            break;
            }
            case 9 :
            s += 31;
            if(y == 9){
            break;
            }
            case 10 :
            s += 30;
            if(y == 10){
            break;
            }
            case 11 :
            s += 31;
            if(y == 11){
            break;
            }
            case 12 :
            s += 30;
            if(y == 12){
            break;
            }
    }
    printf("今天是第%d天\n",s);

• 10.输入三个数，比大小

int a,b,c;
    printf("请输入三个数：");
    scanf("%d%d%d",&a,&b,&c);
    if(a > b)
    {
        if(a > c){
            if(b > c){
            printf("%d>%d>%d\n",a,b,c);
            }else    //b < c
            {
                printf("%d>%d>%d\n",a,c,b);}
        }else//a < c
        printf("%d>%d>%d\n",c,a,b);
    }
    else if(a < b)//a < b
    {
        if(b < c)   
        {
        printf("%d>%d>%d\n",c,b,a);
        }
        else {
            if(a > c){
        printf("%d>%d>%d\n",b,a,c);
        }else 
            printf("%d>%d>%d\n",b,c,a);
        }
    }