1、单分支结构语句
用单分支结构进行奇偶判断：
c#include <stdio.h> int main() { int num; printf("Please enter an integer: "); scanf("%d", &num); if (num % 2 != 0) { printf("%d is odd! \n", num); } if (num % 2 == 0) { printf("%d is even! \n", num); } return 0; }
- 运行结果：
2、双分支结构语句
用双分支结构进行奇偶判断：
c#include <stdio.h> int main() { int num; printf("Please enter an integer: "); scanf("%d", &num); if (num % 2 != 0) { printf("%d is odd! \n", num); } else { printf("%d is even! \n", num); } return 0; }
- 运行结果：
3、多分支结构语句
用多分支结构进行学生成绩的判断：
c#include <stdio.h> int main() { int score; printf("Please enter score: "); scanf("%d", &score); if (score >= 90) { printf("A\n"); } else if (score >= 80) { printf("good\n"); } else if (score >= 70) { printf("medium\n"); } else if (score >= 60) { printf("pass\n"); } else { printf("fail"); } return 0; }
- 运行结果：
4、分支语句的嵌套
判断某学生成绩 score 是否及格：
c#include <stdio.h> int main() { int score; printf("Please enter score: "); scanf("%d", &score); if (score >= 60) { if (score >= 90) { printf("A\n"); } else { printf("pass\n"); } } else { printf("fail\n"); } return 0; }
- 运行结果：
5、switch 选择语句
输入一个简单的四则运算表达式，包含两个实数和一个运算符，输出计算结果：
c#include <stdio.h> int main() { char op; double x, y; printf("Please enter an expression: "); scanf("%lf %c %lf", &x, &op, &y); switch (op) { case '+': printf("The expression results in: %.2f\n", x + y); break; case '-': printf("The expression results in: %.2f\n", x - y); break; case '*': printf("The expression results in: %.2f\n", x * y); break; case '/': printf("The expression results in: %.2f\n", x / y); break; default: printf("Operator error! \n"); } return 0; }
- 运算结果：
6、while 循环结构与执行流程
用 while 循环语句计算输入的 10 个整数和奇数的和：
c#include <stdio.h> int main() { int num; int i = 1, sum = 0; int count = 0; printf("Please enter 10 integers at a time: "); while (i <= 10) { scanf("%d", &num); if (num % 2 != 0) { sum += num; count++; } i++; } if (count == 0) { printf("There are no odd numbers in the data!"); } else { printf("Odd numbers are: %d\n", count); printf("Odd sum: %d", sum); } return 0; }
- 运算结果：
7、for 循环语句与执行流程
打印出所有"水仙花数"：
c#include <stdio.h> int main() { int a, b, c; int i; for (i = 100; i < 1000; i++) { a = i % 10; b = (i / 10) % 10; c = i / 100; if (a * a * a + b * b * b + c * c * c == i) { printf("%d\t", i); } } return 0; }
- 运行结果：
用嵌套 for 循环方式计算 1 到 100 的素数和：
c#include <stdio.h> int main() { int sum = 0, i = 0, j = 0; int count; printf("The prime numbers from 1 to 100 are: "); for (i = 2; i <= 100; i++) { count = 0; for (j = 2; j <= i / 2; j++) { if (i % j == 0) { count++; break; } } if (count == 0) { printf("%d ", i); sum += i; } } printf("\nThe sum of primes from 1 to 100 is: %d", sum); return 0; }
- 运算结果：
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8、do-while 循环结果与执行流程
计算两个数的最大公约数
c#include <stdio.h> int main() { int m, n, r, t; int m1, n1; printf("Please enter the first number: "); scanf("%d", &m); printf("Please enter the second number: "); scanf("%d", &n); m1 = m; n1 = n; if (m < n) { t = m; m = n; n = t; } do { r = m % n; m = n; n = r; } while (r != 0); printf("The greatest common divisor of %d and %d is %d\n", m1, n1, m); return 0; }
- 运行结果：
9、循环结构嵌套
九九乘法表的打印：
c#include <stdio.h> int main() { int i = 0, j = 0; printf("*"); for (i = 1; i <= 9; i++) { printf("%8d", i); } printf("\n"); for (i = 1; i <= 9; i++) { printf("%d", i); for (j = 1; j <= i; j++) { printf("%3d*%d=%2d", i, j, i * j); } printf("\n"); } return 0; }
- 运行结果：
10、辅助语句 break 和 continue
输入大于 2 的整数，判断该数是否为素数：
c#include <stdio.h> int main() { int m, i, flag; flag = 1; printf("Please enter an integer greater than 2: "); scanf("%d", &m); for (i = 2; i < m; i++) { if (m % i == 0) { flag = 0; break; } } if (flag) { printf("%d is prime number! \n", m); } else { printf("%d is not prime number! \n", m); } return 0; }
- 运行结果为
判断 1800 年到 2024 年之间的所有闰年并输出：
c#include <stdio.h> int main() { int year; for (year = 1800; year <= 2024; year++) { if (!(year % 4 == 0 && year % 100 != 0 || year % 400 == 0)) { continue; } printf("%d ", year); if (year % 10 == 0) { printf("\n"); } } return 0; }
- 运行结果：
11、改良的计算器
改良版实现四则运算功能的计算器：
c#include <stdio.h> int main() { double displayed_value; double new_entry; char command_character; printf("Improved computer program\n"); printf("Tip: (number> )Enter number, (command> )Enter Operator +、-、*、/\n"); printf("number> "); scanf("%lf", &displayed_value); getchar(); printf("command> "); scanf("%c", &command_character); while (command_character != 'Q') { switch (command_character) { case 'c': case 'C': scanf("%lf", &displayed_value); break; case '+': printf("number> "); scanf("%lf", &new_entry); displayed_value += new_entry; break; case '-': printf("number> "); scanf("%lf", &new_entry); displayed_value -= new_entry; break; case 'x': case 'X': case '*': printf("number> "); scanf("%lf", &new_entry); displayed_value *= new_entry; break; case '/': printf("number> "); scanf("%lf", &new_entry); while (new_entry == 0) { printf("Divisor cannot be 0, please re-enter! \n"); printf("number> "); scanf("%lf", &new_entry); } displayed_value /= new_entry; break; default: printf("Invalid input, please re-enter the command type! \n"); } printf("Value: %lf\n", displayed_value); getchar(); printf("command> "); scanf("%c", &command_character); } return 0; }
- 运算结果：
