《C和C指针》中转移表的实现

先上代码

#include <stdio.h>   
#include <string.h>   

double add(double a, double b){  
    return a+b;  
}  
double sub(double a, double b){  
    return a-b;  
}  
double mul(double a, double b){  
    return a*b;  
}  
double div(double a, double b){  
    return a/b;  
}
///////////////////////////////
double (*oper_func[])(double, double) = {  
    add, sub, mul, div  
};  

int main()  
{  
    int ifContinue=1;
    int flag=1;
    int oper;  
    double a,b;  
    double result; 
	while(flag){
		printf("Operator:\n0:add	1:sub	2:mul	3:div\n");  
		scanf("%d",&oper); 
		if(oper>3||oper<0){
			printf("input wrong!\n");
			continue;
		}
		printf("a:");  
		scanf("%lf",&a);  
		printf("b:");  
		scanf("%lf",&b);  
		result = oper_func[oper](a, b);  
		printf("result is %lf\n", result); 

		printf("Continue or not:(y/n)\n");
		getchar();//////////用于吃掉前面的‘回车’
		scanf("%c",&ifContinue);
		if(ifContinue=='n')
			flag=0;
	}
    return 0;  
}  

《C和C指针》中说转换表就是一个函数指针数组。

double (*oper_func[])(double, double) = {  
    add, sub, mul, div  
};

默认add是0，sub是1，mul是2，div是3。