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回复 1# zhangchaoy
rand()函数是生成一个随机的非负整数函数。
Example 1
The following example generates a random number restricted to a specific zero-based range using the mod (%) operator.
//srand is called before rand
srand(time(NULL));
/* Generate a random number from 0-99 */
lr_output_message
("A number between 0 and 99: %d\n", rand() % 100);
Output:
Action.c(7): A number between 0 and 99: 72
Example 2
The following example generates a random number, rNum, between 20 and 29 using the mod (%) operator and addition.
int rNum;
//srand is called before rand
srand(time(NULL));
/* The order of evaluation is first rand(), then the modulus,
then the addition. The command below is equivalent to :
rNum = rand() % 10;
rNum is now a number between 0-9
rNum += 20;
rNum is now between 20 and 29
*/
rNum= rand() % 10 + 20;
你的i=rand()%6+15返回的是15-21 |
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