iOS-C 第四天（下）

2.随机数的获取;   
//获取三十个随机数:   
//arc4random();
//获取随机数;   
//    int i = 0;
//    while (i < 30) {
//        unsigned long temp = arc4random() % 31;
//        printf("%lu ",temp);
//        i++;
//    }       
//0~50随机数:
//    int i = 0;
//    while (i < 10) {
//        unsigned int temp = arc4random() % 51;
//        printf("%d ", temp);
//        i++;
//    }       
//20~50随机数:
//    int i = 0;
//    while (i < 10) {
//        unsigned int temp = arc4random() % (50-20+1)+20;
//        printf("%d ", temp);
//        i++;
//    }   
//[x,y]   
//arc4random()%(y - x + 1)+x;       
//20个70~30的随机数,输出最大值:
//    int i = 0,max =0;
//    while (i < 20) {
//        unsigned int temp = arc4random() % (70 - 30 + 1) +30;
//        printf("%d ", temp);
//        max = max > temp ? max : temp;
//        i++;
//    }
//    printf("其中最大的数是:%d ", max);
//       
//    int i = 0;
//    printf("%u ", arc4random() % (70 - 30 +1) +30);       
//%lu unsigned long
//%u unsigned int
//生成50个 100~200的随机数,输出最大最小:       
//最小值初值的设定不能为零;否则生成的随机数永远都不会比0小;
//    int i = 0, min = 200, max = 0;
//    while (i < 50) {
//        unsigned int temp = arc4random() % (200 - 100 + 1) +100;
//        printf("%u ", temp);
//        min = min < temp ? min : temp;
//        max = max > temp ? max : temp;
//        i++;
//    }
//    printf("最大值为:%d, 最小值为:%d ", max,  min);  
 
 
3.do ... while 循环体的使用;   
//do ...while   
//  do {   
//  循环体
//     
}while (条件)   
 
//do ... while 循环和while 循环的区别:  
// do...while 不管条件成不成立,都要先执行一次        
 
//打印0~100的奇数:
//    int i = 1;
//    do{
//        printf("%d ", i);
//        i += 2;
//    } while (i <= 100);   
//if (i % 2 == 1){   
//printf("")
//   
//输入一个数,输出他的位数:
////    int i = 0, count = 0, number = 0;
////    printf("请输入一个数字:");
////    scanf("%d", &number);
////      i = number;
////    do {
//   
////        number = number / 10;
//   
////        count++;
////    } while (number != 0);
////    printf("%d 是一个%d位数 ", i, number);
//
//
////    int i = 0, count = 0, number = 0;
////    printf("请输入一个数字:");
////    while (number != 0) {
////        number /= 10;
////        count++;
////    }
////    if (number == 0){
////        printf("1位数 ");
////    }  

4.for循环结构的使用;    
//for 循环
//    for (语句1 ; 语句2 ; 语句3) {
//        语句4
//    }   
//语句1:初始化   
//语句2:条件表达式   
//语句3:循环增量   
//语句4:循环体   
//执行顺序:第一次 1243 以后243   
//    for (int i = 1; i <= 100; i++) {
//        printf("Hello World! ");
//    }   
//    for (int i = 1; i <= 100; i++) {
//        printf("%d ", i);
//    }
//  
  //    for (int i = 100; i >0; i--) {
//        printf("%d ", i);
//    }       
//打印1~100的偶数:
//    int number = 0;
//    for (int i = 1; i <= 50; i++) {
//        number = i * 2;
//        printf("%d ", number);
//    }
//           
//for 循环 while 循环区别:   
//while 知道循环的条件, for循环知道循环的次数;   
//for 循环变形:(了解)       
//    for (int i = 0, j = 0; i < 100 && j < 50;
//         i++, j++){
//        printf("Hello! ");
//    }
//执行50次;       
//循环的嵌套:   
//外循环控制行数,   
//内循环控制个数;   
//    for (int i = 1; i <= 4; i++) {
//        for (int j = 1; j <= 3; j++) {
//            printf("%d ", j);
//        }printf(" ");
//    }
//    for (int i = 1; i <= 5; i++) {
//        for (int j = 1; j <= 5; j++) {
//            printf("%d ", j);
//        }printf(" ");
//    }   
//    for (int i = 1; i <= 5; i++) {
//        for (int j = 1; j <= i; j++) {
//            printf("%d ", j);
//        }printf(" ");
//    }   
//    for (int i =1; i <= 9; i++) {
//        for (int j = 1; j <= i; j++) {
//            printf("%d × %d =%-2d  ", i, j, i * j);
//        }printf(" ");
//    }   
//    int i = 1, j = 1;
//    printf("请输入要打的行数和字数:");
//    scanf("%d %d", &i, &j)
//    for (int i = 1; i <= 5; i++) {
//            for (int j = 1; j <= i; j++) {
//            printf("%d ", j);
//        }printf(" ");
//    }   
//    for (int i = 0; i <= 9; i++) {
//        for (int j = 0; j <=9; j++) {
//            for (int k = 0; k <= 9; k++) {
//                printf("%03d ", i * 100 + j *10 + k);
//            }printf(" "); //        } //    }   
//循环嵌套建议要不超过3层;   
//两层循环:   
5.break 与 continue 的区别;    
//    for (int i = 1; i < 10;) {
//        if (i == 4) {
//            break;
//        }
//        printf("%d ", i);
//    }   
//break 跳出本层循环;可以把for 看做一层循环       
//    for (int i = 1; i < 10; i++) {
//        for (int j = 1; j < 10; j++) {
//            if (j == 4) {
//                break;
//            }printf("%d ", j);
//        }printf(" ");
//    }       
//continue:在循环中的使用   
//continue:结束本次循环   
//作用:加速循环的执行

 

 

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2.随机数的获取;   
//获取三十个随机数:   
//arc4random();
//获取随机数;   
//    int i = 0;
//    while (i < 30) {
//        unsigned long temp = arc4random() % 31;
//        printf("%lu ",temp);
//        i++;
//    }       
//0~50随机数:
//    int i = 0;
//    while (i < 10) {
//        unsigned int temp = arc4random() % 51;
//        printf("%d ", temp);
//        i++;
//    }       
//20~50随机数:
//    int i = 0;
//    while (i < 10) {
//        unsigned int temp = arc4random() % (50-20+1)+20;
//        printf("%d ", temp);
//        i++;
//    }   
//[x,y]   
//arc4random()%(y - x + 1)+x;       
//20个70~30的随机数,输出最大值:
//    int i = 0,max =0;
//    while (i < 20) {
//        unsigned int temp = arc4random() % (70 - 30 + 1) +30;
//        printf("%d ", temp);
//        max = max > temp ? max : temp;
//        i++;
//    }
//    printf("其中最大的数是:%d ", max);
//       
//    int i = 0;
//    printf("%u ", arc4random() % (70 - 30 +1) +30);       
//%lu unsigned long
//%u unsigned int
//生成50个 100~200的随机数,输出最大最小:       
//最小值初值的设定不能为零;否则生成的随机数永远都不会比0小;
//    int i = 0, min = 200, max = 0;
//    while (i < 50) {
//        unsigned int temp = arc4random() % (200 - 100 + 1) +100;
//        printf("%u ", temp);
//        min = min < temp ? min : temp;
//        max = max > temp ? max : temp;
//        i++;
//    }
//    printf("最大值为:%d, 最小值为:%d ", max,  min);  
 
 
3.do ... while 循环体的使用;   
//do ...while   
//  do {   
//  循环体
//     
}while (条件)   
 
//do ... while 循环和while 循环的区别:  
// do...while 不管条件成不成立,都要先执行一次        
 
//打印0~100的奇数:
//    int i = 1;
//    do{
//        printf("%d ", i);
//        i += 2;
//    } while (i <= 100);   
//if (i % 2 == 1){   
//printf("")
//   
//输入一个数,输出他的位数:
////    int i = 0, count = 0, number = 0;
////    printf("请输入一个数字:");
////    scanf("%d", &number);
////      i = number;
////    do {
//   
////        number = number / 10;
//   
////        count++;
////    } while (number != 0);
////    printf("%d 是一个%d位数 ", i, number);
//
//
////    int i = 0, count = 0, number = 0;
////    printf("请输入一个数字:");
////    while (number != 0) {
////        number /= 10;
////        count++;
////    }
////    if (number == 0){
////        printf("1位数 ");
////    }  

4.for循环结构的使用;    
//for 循环
//    for (语句1 ; 语句2 ; 语句3) {
//        语句4
//    }   
//语句1:初始化   
//语句2:条件表达式   
//语句3:循环增量   
//语句4:循环体   
//执行顺序:第一次 1243 以后243   
//    for (int i = 1; i <= 100; i++) {
//        printf("Hello World! ");
//    }   
//    for (int i = 1; i <= 100; i++) {
//        printf("%d ", i);
//    }
//  
  //    for (int i = 100; i >0; i--) {
//        printf("%d ", i);
//    }       
//打印1~100的偶数:
//    int number = 0;
//    for (int i = 1; i <= 50; i++) {
//        number = i * 2;
//        printf("%d ", number);
//    }
//           
//for 循环 while 循环区别:   
//while 知道循环的条件, for循环知道循环的次数;   
//for 循环变形:(了解)       
//    for (int i = 0, j = 0; i < 100 && j < 50;
//         i++, j++){
//        printf("Hello! ");
//    }
//执行50次;       
//循环的嵌套:   
//外循环控制行数,   
//内循环控制个数;   
//    for (int i = 1; i <= 4; i++) {
//        for (int j = 1; j <= 3; j++) {
//            printf("%d ", j);
//        }printf(" ");
//    }
//    for (int i = 1; i <= 5; i++) {
//        for (int j = 1; j <= 5; j++) {
//            printf("%d ", j);
//        }printf(" ");
//    }   
//    for (int i = 1; i <= 5; i++) {
//        for (int j = 1; j <= i; j++) {
//            printf("%d ", j);
//        }printf(" ");
//    }   
//    for (int i =1; i <= 9; i++) {
//        for (int j = 1; j <= i; j++) {
//            printf("%d × %d =%-2d  ", i, j, i * j);
//        }printf(" ");
//    }   
//    int i = 1, j = 1;
//    printf("请输入要打的行数和字数:");
//    scanf("%d %d", &i, &j)
//    for (int i = 1; i <= 5; i++) {
//            for (int j = 1; j <= i; j++) {
//            printf("%d ", j);
//        }printf(" ");
//    }   
//    for (int i = 0; i <= 9; i++) {
//        for (int j = 0; j <=9; j++) {
//            for (int k = 0; k <= 9; k++) {
//                printf("%03d ", i * 100 + j *10 + k);
//            }printf(" "); //        } //    }   
//循环嵌套建议要不超过3层;   
//两层循环: