作业12

#include<stdio.h>
#include<string.h>
struct student_list
{
    char n1[10];
    int s1;
    int s2;
    int s3;
    char n2[10];
};
int count=0;
void search_student(struct student_list students[],char *n1);
void new_student(struct student_list students[]);
void printf_student(struct student_list students[]);
void average_student(struct student_list students[],double average);
int main()
{
    int choice;
    double average;
    char n1[10];
    struct student_list students[50]; 
    do{
        printf("*****学生信息管理系统*****\n");
        printf("\t1:输入\n");
        printf("\t2:查询\n");
        printf("\t3:输出\n");
        printf("\t4:平均成绩\n");
        printf("\t5:退出\n");
        printf("请选择功能:");
        scanf("%d",&choice);
        switch(choice)
            {
            case 1:
                new_student(students);
                break;
            case 2:
                printf("请输入要查找的联系人名：");
                scanf("%s",n1);
                search_student(students,n1);
                break;
            case 3:                
                printf_student(students);
                break;
            case 4:
                average_student(students,average);
            case 0:
                break; 
            }        
        }while(choice!=0);
}    

void new_student(struct student_list students[])
{
    int i;
    struct student_list s;
    if(count==50)
    printf("数据已满");
    printf("输入姓名:");
    scanf("%s",s.n1);
    printf("输入学号:");
    scanf("%s",s.n2);
    printf("输入三科成绩:");
    scanf("%d%d%d",&s.s1,&s.s2,&s.s3);
    students[count]=s;
    count++;
}

void printf_student(struct student_list students[])
{
    printf("系统中学生为:");
    int x;
    for(x=0;x<count;x++)
    {
        printf("%s %s  %d %d %d",students[x].n1,students[x].n2,students[x].s1,students[x].s2,students[x].s3);    
    }
            
}

void search_student(struct student_list students[],char *name)
{
    int z,a=0;
    if(count==0)
    {
        printf("错误");
        return;
    } 
    for(z=0;z<count;z++)
        if(strcmp(name,students[z].n1)==0)
        {
            a=1;
            break;
        }             
    if(a==1){
        printf("姓名:%s\t",students[z].n1);
        printf("学号:%s\t",students[z].n2);
        printf("分数:%d %d %d\n",students[z].s1,students[z].s2,students[z].s3);
    }
}

void average_student(struct student_list students[],double average)
{
    int c;
    for(c=0;c<count;c++)
        average=(students[c].s1+students[c].s2+students[c].s3)/3;
    printf("平均成绩=%.2lf\n",average);
    return;
}

#include<stdio.h>
#include<string.h>
int main()
{
    char str[100];
    int i,x=0,y=0,z=0,c=0;
    printf("请输入:");
    gets(str);
    for(i=0;str[i]!='\0';i++)
    {
        if(str[i]>='a'&&str[i]<='z')
            x++;
        else if(str[i]>='A'&&str[i]<='Z')
            y++;
        else if(str[i]>='0'&&str[i]<='9')
            z++;
        else if(str[i]==' ')
            c++;
    }
    printf("小写字母:%d\n",x);
    printf("大写字母:%d\n",y);
    printf("数字字符：%d\n",z);
    printf("空格：%d\n",c);
    return 0;
}

#include<stdio.h>
#include<string.h>
int main()
{
     char str[5][10];
     int j[5],x=0,a;
    for(a=0;a<5;a++)
{
      gets(str[a]);
      j[a]=strlen(str[a]);
      if(j[a]>x)
      {
    x=j[a];
      }
}
     for(a=0;a<5;a++)
 {
      if(x==j[a])
       puts(str[a]);
 }
     printf("\n");
     return 0;
}