实验一

task1

task2

#include <stdio.h>
int main()
{
    int n, sum;
    scanf_s("%d", &n);
    int i = 1;
    sum = 0;
    while (i <= n) 
    {
        sum = sum + i;
        i++;
    }
    printf("sum=%d\n", sum);
    return 0;
}

 

写法12可以，34不可以；因为34如果n为奇数在n/2时会向上取整使结果不准确

task3

#include<stdio.h>

int main()
{
    int a, b, t;
    
    a = 3;
    b = 4;
    printf("a=%d,b=%d\n",a,b);
    
    t = a;
    a = b;
    b = t;
    printf("a=%d,b=%d\n",a,b);
    
    return 0;
    
}

回答:交换ab的值

task4

#include <stdio.h>
int main()
{
    int x, m, t;
    x = 123;
    printf("x=%d\n", x);
    t = 0;
    m = x % 10;
    t = t * 10 + m;
    x = x /10;

    m = x % 10;
    t = t * 10 + m;
    x = x /10;

    m = x % 10;
    t = t * 10 + m;
    x = x /10;
    printf("t=%d\n", t);

    return 0;
}

回答:反序

task5

#include <stdio.h>

int main()
{
    float a, b, c;
    scanf("%f%f%f", &a, &b, &c);
    if(a + b > c )
        printf("能构成三角形\n");
    else
        printf("不能构成三角形\n");
        
    return 0; 
 }

 

 

task6

#include <stdio.h>>
int main()
{
   int year;
   
   year = 10000000000/365/24/60/60;
   
   printf("10亿年约等于%d年\n",year);
   
   return 0;
}

task7

//生成一个分数在区间[60-100]之间的随机整数
#include <stdio.h>
#include<stdlib.h>
#include<time.h>
int main()
{
    int n;
    srand((unsigned)time(NULL));
    n=rand()%41+60;
    printf("n = %d\n" , n);
    
    
    return 0;
 }

 

task8

#include <stdio.h>
int main()
{
    char ans1, ans2;
    printf("每次课前认真预习、课后及时复习了没? (输入y或Y表示有，输入n或N表示没有) : ");
    ans1 = getchar();
    getchar();
    printf("\n动手敲代码实践了没? (输入y或Y表示敲了，输入n或N表示木有敲) : ");
    ans2 = getchar();
    if ((ans1=='y'||ans1=='Y' )&&(ans2 == 'y'||ans2=='Y'))
        printf("\n罗马不是一天建成的, 继续保持哦:)\n");
    else
        printf("\n罗马不是一天毁灭的, 我们来建设吧\n");
    return 0;
}