实验一

include <stdio.h>
int main() {
    printf(" O \n");
    printf("<H>\n");
    printf("I I\n");
    printf(" O \n");
    printf("<H>\n");
    printf("I I\n");
return 0; }

 

#include <stdio.h>
int main() {
    printf(" O   O \n");
    printf("<H> <H>\n");
    printf("I I I I\n");
return 0; }

 

#include <stdio.h>
int main() {
    int x, y;
    int r1, r2, r3, r4;

    x = 1; y = 2;
    r1 = x + y;
    r2 = x - y;
    r3 = x * y;
    r4 = x / y;

    printf("r1 = %d\n", r1);
    printf("r2 = %d\n", r2);
    printf("r3 = %d\n", r3);
    printf("r4 = %d\n", r4);

    return 0; 
}

 

#include <stdio.h>
int main() {
    float x, y;
    float r1, r2, r3, r4;

    x = 1; y = 2;
    r1 = x + y;
    r2 = x - y;
    r3 = x * y;
    r4 = x / y;

    printf("r1 = %f\n", r1);
    printf("r2 = %f\n", r2);
    printf("r3 = %f\n", r3);
    printf("r4 = %f\n", r4);

    return 0; 
}

 原因：整形不显示小数点后数字，浮点型显示小数点后数字

#include <stdio.h>
int main() {
    int n, r1, r2, r3, r4;
    n = 100;

    r1 = n*(n+1)/2;
    r2 = (n+1)*n/2;
    r3 = n/2*(n+1);
    r4 = (n+1)/2*n;

    printf("n = %d\n", n);
    printf("r1 = %d\n", r1);
    printf("r2 = %d\n", r2);
    printf("r3 = %d\n", r3);
    printf("r4 = %d\n", r4);
    return 0; 
}

 

#include <stdio.h>
int main() {
int n, r1, r2, r3, r4;
n = 101;


    r1 = n*(n+1)/2;
    r2 = (n+1)*n/2;
    r3 = n/2*(n+1);
    r4 = (n+1)/2*n;



    printf("n = %d\n", n);
    printf("r1 = %d\n", r1);
    printf("r2 = %d\n", r2);
    printf("r3 = %d\n", r3);
    printf("r4 = %d\n", r4);
    return 0; 
}

公式：n（n+1）/2    （n+1)n/2   n/2(n+1)   (n+1)/2n 

原因：整型数据中小数部分会被舍去，所以奇数除以二时只会取整数部分，所以会存在误差。

#include<stdio.h>
int main() {
    double x,y;
    char c1,c2,c3;
    int a1,a2,a3;
    scanf("%d%d%d",&a1,&a2,&a3);
    printf("%d,%d,%d\n",a1,a2,a3);
    scanf("%c%c%c",&c1,&c2,&c3);
    printf("%c%c%c\n",c1,c2,c3);
    scanf("%lf,%lf",&x,&y);
    printf("%lf,%lf\n",x,y);
    return 0; 
}

 

 

 

#include<stdio.h>
int main() {
    double x,y;
    char c1,c2,c3;
    int a1,a2,a3;
     scanf("%d%d%d",a1,a2,a3);
    printf("%d,%d,%d\n",a1,a2,a3);
    scanf("%c%c%c",&c1,&c2,&c3);
    printf("%c%c%c\n",c1,c2,c3);
    scanf("%f,%lf",&x,&y);
    printf("%f,%lf\n",x,y);
return 0; }

 

#include <stdio.h>
int main(){
    int answer;
    char words[5000];
    printf("网课学习让一些人欢喜一些人忧.\n");
    printf("1. 作为一个宅，社恐，觉得这样很好. 有网络，自主学习，很ok.\n"); printf("2. 不喜，不喜，很不喜. 眼睛快瞎了. 脑壳有点卡...\n"); printf("3. 中间派. 不知道. 说不清.\n");
    printf("4. 其它...\n");
    printf("你的选择: ");
    scanf("%d", &answer);
    if(answer == 4) {
    printf("请补充说明你的想法: \n");
    getchar();
}
    printf("\n");
    printf("当遇到问题时, 你会选择:\n");
    printf("1. 遇到问题, 就解决问题。不懂的，搜索式学习，逐个攻破.\n"); printf("2. 遇到问题, 不高兴。然后,...,没有了.\n");
    printf("3. 其它...\n");
    printf("你的选择: ");
    scanf("%d", &answer);
    if(answer == 1)
        printf(":)\n");
    else if(answer == 2) printf("这样不能解决问题啊...我们选择1好不好:)\n");
    else if(answer == 3) {
    printf("请补充说明你的想法: \n");
    getchar();
    }
    return 0;
}