//
// Created by 衝哥 on 2020/12/29.
//
#include "stdio.h"
int main() {
int i, j, result;
for (i = 1; i < 10; i++) {
for (j = 1; j <= i; j++) {
result = i * j;
printf("%d*%d=%-4d", i, j, result);
}
printf("\n");
}
return 0;
}
2、古典問題：有一對兔子，從出生後第3個月起每個月都生一對兔子，小兔子長到第三個月後每個月又生一對兔子，假如兔子都不死，問每個月的兔子總數為多少？//
// Created by 衝哥 on 2020/12/29.
//
#include "stdio.h"
int main() {
long f1, f2;
int i;
f1 = f2 = 1;
for (i = 1; i <= 20; i++) {
printf("%12ld %12ld", f1, f2);
if (i % 2 == 0) printf("\n");/*控制輸出，每行四個*/
f1 = f1 + f2; /*前兩個月加起來賦值給第三個月*/
f2 = f1 + f2; /*前兩個月加起來賦值給第三個月*/
}
return 0;
}
3、判斷101-200之間有多少個素數，並輸出所有素數及素數的個數。程序分析：判斷素數的方法：用一個數分別去除2到sqrt(這個數)，如果能被整除，則表明此數不是素數，反之是素數。
//
// Created by 衝哥 on 2020/12/29.
//
#include "stdio.h"
#include "math.h"
int main() {
int m, i, k, h = 0, leap = 1;
printf("\n");
for (m = 101; m <= 200; m++) {
k = sqrt(m + 1);
for (i = 2; i <= k; i++)
if (m % i == 0) {
leap = 0;
break;
}
if (leap) /*內循環結束後，leap依然為1，則m是素數*/
{
printf("%-4d", m);
h++;
if (h % 10 == 0)
printf("\n");
}
leap = 1;
}
printf("\nThe total is %d", h);
return 0;
}
4、個數如果恰好等於它的因子之和，這個數就稱為"完數"。例如6=1＋2＋3.編程找出1000以內的所有完數。//
// Created by 衝哥 on 2020/12/29.
//
#include "stdio.h"
int main() {
static int k[10];
int i, j, n, s;
for (j = 2; j < 1000; j++) {
n = -1;
s = j;
for (i = 1; i < j; i++) {
if ((j % i) == 0) {
n++;
s = s - i;
k[n] = i;
}
}
if (s == 0) {
printf("%d is a 完數: ", j);
for (i = 0; i < n; i++)
printf("%d,", k[i]);
printf("%d\n", k[n]);
}
}
return 0;
}
5、編程列印直角楊輝三角形//
// Created by 衝哥 on 2020/12/29.
//
#include "stdio.h"
int main() {
int i, j, a[6][6];
for (i = 0; i <= 5; i++) {
a[i][i] = 1;
a[i][0] = 1;
}
for (i = 2; i <= 5; i++)
for (j = 1; j <= i - 1; j++)
a[i][j] = a[i - 1][j] + a[i - 1][j - 1];
for (i = 0; i <= 5; i++) {
for (j = 0; j <= i; j++)
printf("%4d", a[i][j]);
printf("\n");
}
return 0;
}
6、將輸入的字符串反序輸出//
// Created by 衝哥 on 2020/12/29.
//
#include "stdio.h"
#include <string.h>
int main() {
char c[200], c1;
int i, j, k;
printf("Enter a string: ");
scanf("%s", c);
k = strlen(c);
for (i = 0, j = k - 1; i < k / 2; i++, j--) {
c1 = c[i];
c[i] = c[j];
c[j] = c1;
}
printf("%s\n", c);
return 0;
}
7、在一個字串s1中查找一子串s2，若存在則返回子串在主串中的起始位置，不存在則返回-1。//
// Created by 衝哥 on 2020/12/29.
//
#include "stdio.h"
#include <string.h>
int main() {
char s1[6] = "thisis";
char s2[5] = "is";
printf("%d\n", search(s1, s2));
return 0;
}
int search(char s1[], char s2[]) {
int i = 0, j, len = strlen(s2);
while (s1[i]) {
for (j = 0; j < len; j++)
if (s1[i + j] != s2[j]) break;
if (j >= len)return i;
else i++;
}
return -1;
}
8、輸入一個字符串，判斷其是否為回文。回文字符串是指從左到右讀和從右到左讀完全相同的字符串。//
// Created by 衝哥 on 2020/12/29.
//
#include <stdio.h>
#include <string.h>
#include<string.h>
int main() {
char s[100];
int i, j, n;
printf("輸入字符串：\n");
gets(s);
n = strlen(s);
for (i = 0, j = n - 1; i < j; i++, j--)
if (s[i] != s[j]) break;
if (i >= j) printf("是回文串\n");
else printf("不是回文串\n");
return 0;
}
8、用指針變量輸出結構體數組元素。//
// Created by 衝哥 on 2020/12/29.
//
#include <stdio.h>
struct student {
int num;//學號
char *name;//姓名
char sex;//性別
int age;//年齡
} stu[5] = {{1001, "張三", 'F', 18},
{1002, "李四", 'M', 28},
{1003, "王五", 'F', 34},
{1004, "趙六", 'F', 25},
{1005, "前七", 'M', 19}};
int main() {
int i;
struct student *ps;
printf("Num \tName\t\t\tSex\tAge\t\n");
//用指針變量輸出結構體數組元素。
for (ps = stu; ps < stu + 5; ps++)
printf("%d\t%-10s\t\t%c\t%d\t\n", ps->num, ps->name, ps->sex, ps->age);
printf("************************************\n");
//用數組下標法輸出結構體數組元素學號和年齡。
for (i = 0; i < 5; i++)
printf("%d\t%d\t\n", stu[i].num, stu[i].age);
return 0;
}