C语言初步之(一)：计算器

C语言的学习已经有一段日子了。写了一个简单的计算器程序。以此来检查自己的学习结果。

并且希望能够得到牛人的指点。能够在编程风格和逻辑方面得到提升。献丑了。

 

/*
 * Calcultor.c
 * Author:
 * Data:
 * Compiler:vs2010
 *
*/
#include<stdio.h>


int getOption(void);
void printResult(void);

float add(float num1, float num2);
float sub(float num1, float num2);
float mul(float num1, float num2);
float div(float num1, float num2);

int
main(void)
{
    printResult();
}//main

void
printResult(void)
{
    float num1;
    float num2;
    int option;

    printf("Please input 2 number: ");
    scanf("%f %f", &num1, &num2);

    switch(option)
    {
    case 1:  printf("The add: %f\n", add(num1, num2));
        break;
    case 2: printf("The sub: %f\n", sub(num1, num2));
        break;
    case 3: printf("The mul: %f\n", mul(num1, num2));
        break;
    case 4: if(num2 != 0)
              printf("The div: %f\n", div(num1,num2));
            else
              printf("Fatal Error.\n");
        break;
    case 5: printf("Thank you for using Calcultor.\n");
    }//switch
}

//打印菜单
int
getOption(void)
{
    int option;

    do
    {
        printf("\n*****************************\n");
        printf("\n          Menu               \n");
        printf("\n# 1. Addition                \n");
        printf("\n# 2. Subtraction             \n");
        printf("\n# 3. Multiplication          \n");
        printf("\n# 4. Division                \n");
        printf("\n# 5. Exit                    \n");
        printf("\n*****************************\n");

        printf("After input, Press Enter.");
        printf("\nNow, Please enter your choice: ");
        scanf("%d", &option);

        if(option < 1 || option > 5)
            printf("\nInvalid option.Please try again.\n");
    }while(option < 1 || option > 5 );//do....while
    return option;
}//getOption

//加法运算
float
add(float num1, float num2)
{
    return num1 + num2;
}//add

//减法运算
float
sub(float num1, float num2)
{
    return num1 - num2;
}//sub

//乘法运算
float
mul(float num1, float num2)
{
    return num1 * num2;
}//mul

//除法运算
float
div(float num1, float num2)
{
    return num1 / num2;
}//div