c primer plus 习题答案(7)

p421.5

#include<stdio.h>
#include<stdlib.h>
#define CSIZE 4
#define SCORE 3

void get_info(struct students *p);
void get_average(struct students *p);
void print_info(struct students *p);
void print_class_average(struct students *p);

struct names{
    char firstname[40];
    char lastname[40];
};

struct students{
    struct names name;
    float grade[SCORE];
    float average;
};

int main(void)
{
    struct students sheet[CSIZE]={
        {{"absbs", "bdcdc"}, 0, 0, 0, 0},
        {{"cfvfv", "dfgfg"}, 0, 0, 0, 0},
        {{"enmnm", "fcvcv"}, 0, 0, 0 ,0},
        {{"ghbhb", "hiyiy"}, 0, 0, 0, 0}
    };


    get_info(sheet);
    get_average(sheet);
    print_info(sheet);
    print_info(sheet);

    system("pause");
    return 0;
}

void get_info(struct students *p)
{
    int i,j;
    for(i=0; i<CSIZE; i++){
        puts("please input student name");
        scanf("%s%s",&((p+i)->name.firstname),&((p+i)->name.lastname));
        puts("input the score");
        for(j=0; j<SCORE; j++)
            scanf("%f",&((p+i)->grade[j]));
    }
}

void get_average(struct students *p)
{
    float sum; 
    int i, j;
    for(i=0; i<CSIZE; i++){
        for(j=0, sum=0; j<SCORE; j++)
        sum+=((p+i)->grade[j]);
        (p+i)->average=sum/SCORE;
    }
}

void print_info(struct students *p)
{
    int i, j;
    for(i=0; i<CSIZE; i++){
        printf("%s	%s
", (p+i)->name.firstname, (p+i)->name.lastname);
        printf("grade:
");
        for(j=0; j<SCORE; j++)
            printf("%f ",(p+i)->grade[j]);
        printf("
");
        printf("the average grade is %.2f", (p+i)->average);
    }
}

void print_class_average(struct students *p)
{
    int i;
    float sum=0;

    for(i=0; i<CSIZE; i++)
        sum+=(p+i)->average;

    printf("the class average grade is %.2f", sum/CSIZE);
}