C语言的基本练习（002-1）之简易菜单选项与三角函数值计算

有关c语言进行简单的输入菜单选择，并由此进行三角函数的简单计算。代码如下：

#include<stdio.h>
#include<math.h>

float theta = 0.0;

int value = 0;

int main(){
    
    printf("please input the size the angle:%f\n",theta);
    printf("if you want to calculate the value os sin, please input 1,else input 2 to ca"\
    "lculate cos,else if the value is 3 , it will calculate tan().\n");
    scanf("%d",&value);
    if(value==1){
    scanf("%f",&theta);
    printf("the sin value of this angle is %f.\n",sin((double)theta));
    }
    else if(value == 2){
    scanf("%f",&theta);
    printf("the cos value of this angle is %f.\n",cos((double)theta));       
    }
    else if(value == 3){
    scanf("%f",&theta);
    printf("the tan value of this angle is %f.\n",tan((double)theta)); 
    }
    
}

具体效果如下：

 

由此可见，不在菜单选项之内，将不会有答案输出。如有疑问，请您留言。