[C++知识库]Faye---c语言day02

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <float.h>

float rnd(){
    //(float)  RAND_MAX  代表将变量RAND_MAX 强制转换为float
    return rand()/(float) RAND_MAX;
}

int main(){
    srand(2);// 随机种子确定, 随机情况就确定了
    printf("float = %f" , rnd());
    return 0;

}
// Returns a random value between 0.0 and 1.0

猜数字游戏

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include "mylibs.h"
int rnd1();//函数的原型声明
int main() {
    // time(NULL) 是时间戳 返回的是1970年1月1日到现在的毫秒数
    // unsigned int 无符号整型
    srand((unsigned int)time(NULL));
    int generate_number = rnd1();
//    printf("pgenerate_number =%d \n", generate_number);
    int guess_number;
    while (1){
        printf("please input a number\n");
        scanf("%d", &guess_number);
//        printf("guess_number = %d\n", guess_number);
        if (guess_number > generate_number){
            printf("too large\n");
        } else if(guess_number < generate_number){
            printf("too small\n");
        }else{
            printf("right ! \n");
            break;
        }
    }
    return 0;
}