簡(jiǎn)單實(shí)用——C語(yǔ)言入門程序練習(xí)

#include
#include
struct structstudent//創(chuàng)建結(jié)構(gòu)體，表示學(xué)生信息
{
??? int No;//學(xué)號(hào)
??? char Name[20];//姓名
??? int Age;//年齡
}
student[3];
void saveFile()//創(chuàng)建函數(shù)，寫入文本
{
??? int i;//循環(huán)變量
??? FILE *fp;//聲明指向結(jié)構(gòu)體的指針
??? if((fp=fopen("c:\\stu.txt","w"))==NULL)//打開文件
??? {
??????? puts("can not open file");//文件打開失敗
??????? exit(1);
??? }
??? for(i=0;i<3;i++)//打開成功
??? {
?????? if (fwrite(&student[i],sizeof(struct structstudent),1,fp)!=1);//寫入
??? ???????????? //第一個(gè)元素，??? 大小，?????? 1個(gè)數(shù)據(jù)塊，文件指針
??? ?? {
??????? ?? puts("write file error");
??????? ?? fclose(fp);//關(guān)閉文件
??????? ?? exit(2);
??? ?? }
??? }//第一個(gè)元素，大小，1個(gè)數(shù)據(jù)塊，文件指針
??? fclose(fp);
}
void printFile()//讀取數(shù)據(jù)打印到屏幕
{
??? int i=0;
??? FILE *fp;
??? struct structstudent *sp;//聲明指針
??? if((fp=fopen("c:\\stu.txt","r"))==NULL)//只讀操作
??? {
??????? puts("can not open file");
??????? exit(1);
??? }
??? printf("studentNo\t\Name\tAge\n");//表頭
??? sp=&student[0];//取第一個(gè)元素的地址,結(jié)構(gòu)體地址
??? for(;i<3;i++,sp++)//讀操作
??? {
??????? if(fread(sp,sizeof(struct structstudent),1,fp)==1)//讀入
??????? {
??????????? printf("%d\t\t%s\t\t%d\n",sp->No,sp->Name,sp->Age);//打印
??????? }?????????? // 制表符?????? 指針 指向運(yùn)算符
??? }
??? fclose(fp);//關(guān)閉文件
}
void main()
{
??? int i;
??? puts("please input student's number,Name,Age:");
??? for(i=0;i<3;i++)
??? {
??????? scanf("%d%s%d",&student[i].No,&student[i].Name,&student[i].Age);
??? }//調(diào)用函數(shù)，文件數(shù)據(jù)塊，
??? saveFile();???? //先寫
??? printf("===student info ===\n");
??? printFile();//再讀
}

#include
main()
{
??? int x,y,z,t;
??? scanf("%d%d%d",&x,&y,&z);
??? if(x>y)
??? {
??????? t=x;x=y;y=t;
??? }
??? if(y>z)
??? {
??????? t=y;y=z;z=y;
??? }
??? if(z>x)
??? {
??????? t=z;z=x;x=t;
??? }
??? printf("small to big:%d %d %d\n",x,y,z);
}

#include
main()
{
??? long f1,f2;
??? int i;
??? f1=f2=1;
??? for(i=1;i<=20;i++)
??? {
??????? printf("%12ld%12ld",f1,f2);
??????? if(i%2==0)
???????
??????????? printf("\n");
??????? ??? f1=f1+f2;
??????? ??? f2=f1+f2;
???????
??? }

?
?
**#include
main()
{
??? int i,j,k,n;
??? printf("water flowers is: ");
??? for(n=100;n<1000;n++)
??? {
??????? i=n/100;
??????? j=n/10%10;
??????? k=n%10;
??????? if(n==i*i*i+j*j*j+k*k*k)
??????????? printf("%-5d",n);
??? }