task1

#include <stdio.h>
#include <stdlib.h>
int main()
{
    printf(" o\n");
    printf("<H>\n");
    printf("I I\n");
    system("pause");

    return 0;
}

 

 

#include <stdio.h>

int main()
{
    int n, sum;
    scanf_s("%d", &n);
    sum = n * (n + 1) / 2;
    printf("sum = %d\n", sum);

 

return 0;
}

#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;
}

#include <stdio.h>
int main()
{
    int x, t, m;
    x = 654;
    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;
}

把百位和个位换位

#include <stdio.h>
int main()
{
    float a, b, c;
    scanf_s("%f%f%f", &a, &b, &c);
    if (((a+b)>c)&&((a+c)>b)&&((b+c)>a))
        printf("能构成三角形\n");
    else
        printf("不能构成三角形\n");
    return 0;
}

#include <stdio.h>
int main()
{
    int year;
    year = 10 ^ 9 / 365 / 24 / 60 / 60;
    printf("10亿秒约等于%d年\n", year);
    return 0;
}

#include <stdio.h>
int main()
{
    int n;
    srand((unsigned)time(NULL));
    n = rand() % 41+60;
    printf_s("n = %d\n", n);
    return 0;
}

#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_s("\n罗马不是一天建成的, 继续保持哦:)\n");
    
    else 
        printf_s("\n罗马不是一天毁灭的, 我们来建设吧\n");
    return 0;
}