struct and union example

1. StructHandler.c:

/*
 * StructHandler.c
 *
 *  Created on: Jul 6, 2013
 *      Author: wangle
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void modifyName(struct student *p);

int main(){
    struct student{
        char name[50];
        char dep[50];
        long no;
        float score[4];
    };

typedef struct student stu_t;

struct student stu[50]={
        "wangle", "Math", 80,80,90.5,99,100,
        "xuyehui", "biological", 90,90,90,70,100,
        "mengmeng", "Math", 100,100,100,100,90
    };
    int i;
    for(i=0; i<3; i++){
        printf("%s, %s, %ld, %.2f,%.2f,%.2f,%.2f\n", stu[i].name, stu[i].dep, stu[i].no,
                stu[i].score[0], stu[i].score[1], stu[i].score[2], stu[i].score[3]);
    }

stu_t * p = stu;
    puts((*(p+1)).name);     //(1) a pointer call style.
    puts((p+1)->name);       //(2) common pointer call style. (1) and (2) is the same.

printf("%s\n", (p+2)->name);
    printf("%s\n", (*(p+2)).name);
    printf("no = %ld\n", p->no);
    void modifyName(struct student * p){
            p->no = 123456;
    }

modifyName(p);
    printf("%s\n", (p)->name);
    printf("no = %ld\n", p->no);
}

2. UnionHandler.c

/*
 * UnionHandler.c
 *
 *  Created on: Jul 6, 2013
 *      Author: wangle
 */

#include <stdio.h>
int main(){
    union unidate{
        char c;
        int i;
        long l;
        float f
    };
    union unidate x;
    x.c=65;
    printf("c=%c\n", x.c);
    x.i = 10;
    printf("i=%d\n",x.i);
    x.l = 100;
    printf("l=%ld\n", x.l);
    x.f = 90.5;
    printf("f=%.1f\n", x.f);
    printf("c=%c\n", x.c);
}