小工具

1.简易计算器（实现加减乘除)

#include <stdio.h>

int main()
{
	double num1;
	double num2;
	char operation;
	double result;

	printf("
Enter the calculation:
");
	scanf("%lf%c%lf", &num1, &operation, &num2);
	switch (operation)
	{
		case'+':
                {
			result = num1 + num2;
			break;
                }
		case'-':
                {
			result = num1 - num2;
			break;
                }
		case'*':
                {
			result = num1 * num2;
			break;
                } 
		case'/':
                {
			result = num1 / num2;
			break;
                }
	}
	printf("%lf", result);
	return 0;
}

2.通讯录