rand() 隨機
#include<stdio.h>
#include<stdlib.h>
int main() {
for (int i = 0; i < 10; i++)
{
printf("%d \n", rand());
}
return 0;
}
srand() 隨機 (設置一個種子)
#include<stdio.h>
#include<stdlib.h>
#include<time.h>
int main() {
srand(11);
for (int i = 0; i < 10; i++)
{
printf("%d \n", rand());
}
int seed = time(NULL);
srand(seed);
for (int i = 0; i < 10; i++)
{
printf("%d \n", rand());
}
return 0;
}
srand() 指定範圍隨機
#include<stdio.h>
#include<stdlib.h>
#include<time.h>
int main() {
srand(time(NULL));
for (int i = 0; i < 10; i++)
{
printf("%d \n", rand() % 90 + 200);
}
return 0;
}
隨機0.00 ~ 1.00之間的double
#include<stdio.h>
#include<stdlib.h>
#include<time.h>
int main() {
srand(time(NULL));
int r = rand() % 100;
double rp = r / 100.0;
printf("%.2f \n", rp);
double rp2 = (double)rand() / RAND_MAX;
printf("%.2f \n", rp2);
return 0;
}
srand() 隨機0-9之間的數
#include<stdio.h>
#include<stdlib.h>
#include<time.h>
int main() {
srand(time(NULL));
int r = rand() % 10;
printf("%d \n", r);
return 0;
}
隨機整數範圍內的小數
#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#include<string.h>
int main() {
srand(time(NULL));
int r = rand() % 60 + 100;
double rp = r + (double)rand() / RAND_MAX;
printf("%.2f \n", rp);
return 0;
}