[C++知识库]C语言实例一：（输出“Hello World“、输出整数、输出单个字符、输出浮点数、输出双精度数、两个数字相加、两个浮点数相乘、两数相除、数值比较）

1.输出“Hello, World！"

#include<stdio.h>

int main(void)
{
	printf("Hello, World!\n");
}

2.输出整数

#include<stdio.h>

int main(void)
{
	int num;

	printf("Please input a number:");

	scanf_s("%d", &num);

	printf("The number you input is:%d\n", num);

}

3.输出单个字符

#include<stdio.h>

int main(void)
{
	char ch;

	printf("Please input a char:");

	scanf_s("%c", &ch);

	printf("The char you input is:%c\n", ch);

}

4.输出浮点数

int main(void)
{
	float fnum;

	printf("Please input a float number:");

	scanf_s("%f", &fnum);

	printf("The float number you input is:%.6f\n", fnum);

}

5.输出双精度数

#include<stdio.h>

int main(void)
{
	double dnum;

	printf("Please input a double number:");

	scanf_s("%lf", &dnum);

	printf("The double number you input is:%.12lf\n", dnum);

}

6.两个数字相加

#include<stdio.h>

int main(void)
{
	int fnum, snum, sum;

	printf("Please input two numbers(divided by blank):");

	scanf_s("%d %d", &fnum, &snum);
	sum = fnum + snum;

	printf("The sum of the two numbers is: %d\n", sum);
}

7.两个浮点数相乘

#include<stdio.h>

int main(void)
{
	double fnum, snum, product;

	printf("Please input two double numbers(divided by blank):");

	scanf_s("%lf %lf", &fnum, &snum);
	product = fnum * snum;

	printf("The product of the two double numbers is: %.3lf\n", product);
}

8.字符转ASCII码

ASCII码表

#include<stdio.h>

int main(void)
{
	char ch;

	printf("Please input a char:");

	scanf_s("%c", &ch);

	printf("The char you input is: %c\n", ch);
	printf("The ASCII of the char you input is: %d\n", ch);

}

9.两数相除?

#include<stdio.h>

int main(void)
{
	int fnum, snum, quotient, remainder;

	printf("Please input two numbers(divided by blank):");

	scanf_s("%d %d", &fnum, &snum);

	while(snum == 0) {
		printf("Error input, please input again:");
		scanf_s("%d %d", &fnum, &snum);
	}

	quotient = fnum / snum;
	remainder = fnum % snum;

	printf("The quotient of the two numbers is: %d\n", quotient);
	printf("The remainder of the two numbers is: %d\n", remainder);
}

10.数值比较

#include<stdio.h>

int main(void)
{
	int fnum, snum;

	printf("Please input two numbers(divided by blank):");

	scanf_s("%d %d", &fnum, &snum);

	if (fnum > snum) {
		printf("The first number is bigger than the second.\n");
	}
	else if (fnum < snum) {
		printf("The first number is smaller than the second.\n");
	}
	else {
		printf("The first number is equal to the second.\n");
	}

}

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