【C】函数

函数实现乘法口诀表

#define _CRT_SECURE_NO_WARNINGS 
#include 
#include 
#include 
#include 
int ride(int i, int j) {
	int result;
	result = i * j;
	return result;
}
int main() {
	int n;
	printf("请输入乘法口诀阶数：");
	scanf("%d", &n);
	for (int i = 1; i <= n; ++i) {
		for (int j = 1; j <= i; ++j) {
			printf("%d*%d = %d  ", i, j, ride(i,j) );
		}
		putchar('\n');
	}
	system("pause");
}

两个数交换

#define _CRT_SECURE_NO_WARNINGS 
#include 
#include 
#include 
#include 
void exchange(int *x, int *y) {
	int temp = *x;
	*x = *y;
	*y = temp;
}
int main() {
	int x;
	int y;
	printf("请输入两个不同的数:\n");
	scanf("%d %d", &x,&y);
	exchange(&x, &y);
	printf("A=%d B=%d\n", x, y);
	system("pause");
}

判断闰年

#include 
#include 
int is_Leapyear(int year) {
	if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) {
		return 1;
	} else {
		return 0;
	}
}
int main() {
	int year;
	int a;
	printf("请输入想要判断的年份：");
	scanf("%d", &year);
	if (is_Leapyear(year)) {
		printf("闰年\n");
	} else {
		printf("非闰年\n");
	}
	system("pause");
}

全局变量令函数返回值为字符转

#include 
#include 
char gs[100];
char is_Leapyear(int *year) {
	if (*year % 4 == 0 && *year % 100 != 0 || *year % 400 == 0) {
		strcpy(gs, "是闰年");
	} else {
		strcpy(gs, "不是闰年");
	}
	return gs;
}
int main() {
	int year;
	printf("请输入想要判断的年份：");
	scanf("%d", &year);
	is_Leapyear(&year);
	printf("%s\n",gs );
	system("pause");
}

实现函数初始化数组 清空数组 数组元素的逆置

#define _CRT_SECURE_NO_WARNINGS 
#include 
#include 
#include 
#include 
void init(int* a) {
	for (int n = 0; n < 10; ++n) {
		int ran = rand() % 100;
		a[n] = ran;
	}
}
void empty(int* a) {
	for (unsigned int n = 0; n < 10; ++n) {
		a[n] = '\0';
	}
}
void reverse(int* a) {
	for (int n = 0; n < 10; ++n) {
		int tmp = a[n];
		a[n] = a[9 - n];
		a[9 - n] = tmp;
	}
}
int main(){
	int a[10] = {0,1,2,3,4,5,6,7,8,9};
	srand((unsigned)time(NULL));
	int n;
	printf("请输入您所需要的操作命令：\n 1 初始化数组\n 2 清空数组\n 3 数组元素逆置\n");
	scanf("%d", &n);
	switch (n) {
	case 1:
		init(a);//初始化数组
		for (int i = 0; i < 10; ++i) {
			printf("%d ",a[i] );
		}
		putchar('\n');
		break;
	case 2:
		init(a);
		for (int i = 0; i < 10; ++i) {
			printf("%d ", a[i]);
		}
		putchar('\n');
		empty(a);//清空数组
		for (int i = 0; i < 10; ++i) {
			printf("%d ", a[i]);
		}
		putchar('\n');
		break;
	case 3:
		init(a);
		for (int i = 0; i < 10; ++i) {
			printf("%d ", a[i]);
		}
		putchar('\n');
		reverse(a);
		for (int i = 0; i < 10; ++i) {
			printf("%d ", a[i]);
		}
		putchar('\n');
		
		break;
	default:
		break;
	}
	system("pause");
}

判断素数

#define _CRT_SECURE_NO_WARNINGS 
#include 
#include 
#include 
#include 
int is_prime(int *n) {
	for (int i = 2; i < *n; ++i) {
		if (*n % i == 0) {
			return 0;
		} 
		if (i == *n - 1) {
			return 1;
		}
	}	
}
int main() {
	int n;
	printf("请输入一个需要判断的数字：");
	scanf("%d", &n);
	if (is_prime(&n)) {
		printf("是素数\n");
	} else {
		printf("不是素数\n");
	}
	system("pause");
}