C經典函數指標的三種使用方式

定義方式：int(*p)(intx,inty);#include<stdio.h>intsum(intx,inty){returnx+y;}intreduce(intx,inty){returnx-y;}intmultiply(intx,inty){returnx*y;}floatdivide(intx,inty){if(y==0)return0;elsereturnx*1.0f/y;}structStudent{intage;floatweight;char*name;void(*studentP());}intmain(intargc,constchar*argv[]){//1.定義函數指標int(*p)(intx,inty);//2.初始化p=sum;//3.賦值ints=p(3,2);//4.列印printf("%d\n",s);//=5;//--------------printf("請輸入數字1,2,3,4\n");intnum;scanf("%d",&num);switch(num){case1:p=sum;break;case2:p=reduce;break;case3:p=multiply;break;case4:p=divide;break;}intresult=p(22,2);printf("%d\n",result);//結構體：structStudentstu=(22,88,"tom",studp);printf("結構體長度=%d",sizeof(stu));//1.stu.studp;//2.structstu*stp=&stu;(*stp).studp;//3.stp->studp;return0;}