為什么要使用函 voidmainintm_num,scanf("%d",m_result=qiuJieCheng(m_num);printf("%d的階乘為：%d\n",m_num,}intqiuJieCheng(intnum){inti=1,result=1;while(i<=num){result=result*i=i+}return}函數(shù)機制的優(yōu) 常用內(nèi)置函 doublesqrt(double計算xdoublepow(doublex,double計算x的ydoubleceil(double求不小于x的最小整數(shù)，并以doubledoublefloor(double求不大于x的最大整數(shù)，并以doubleinttoupper(int如果xinttolower(int如果xintvoidexit(int內(nèi)置函數(shù)sqrt和pow示 #include#include<math.h>voidmain(){intdoublesquareroot,power;while(x<=10){printf(d的平方根:%3.2f\t%d1的平方根: 2的平方根: 3的平方根: 4的平方根: 5的平方根: 5的立方:6的平方根: 6的立方:7的平方根: 7的立方:8的平方根: 8的立方:9的平方根: 9的立方:10的平方根:3.16 10的立方:1000Pressanykeytocontinue}}==#include<stdio.h>#include<math.h>voidmain(){printf("\nfloor(99.1)=%f\n",floor(99.1))printf("floor(-99.1)=%f\n",floor(-99.1));printf("floor(99.9)=printf("floor(-99.9)=%f\n",floor(-99.9));printf("\nceil(99.1)=%f\n",ceil(99.1));printf("ceil(-99.1)=%f\n",ceil(-floor(99.1)=99.000000floor(-99.1)=-floor(99.9)=floor(-99.9)=-ceil(99.1)=100.000000ceil(-99.1)=-ceil(99.9)=ceil(-99.9)=-Pressanykeyto}printf("ceil(99.9)=printf("ceil(-99.9)=%f\n",ceil(- voidmain(){charmsg1,msg2,to_upper,to_lower;printf("}Pressanykeyto voidmain(){intprintf("10099for(i=0;i<10;i++)printf("%d",rand()%100);}10099447326583794274228PressanykeytovoidvoidyDiscount()printf("f",}floatpricediscount_amt;scanf("%f,&price);discount_amt=0.75*doublemax(doublex,doubley){doublem;returnm;}函數(shù)原型說 #include#include<stdio.h>floatcount(int,voidmain()....}floatcount(intx,inty)..}函數(shù)調(diào)用形 voidmain(){ }

float{}float {}函數(shù)嵌套調(diào) voidmain(){}

void{}void{

}}函數(shù)遞歸調(diào) intfactorial(intif(a==1){return1;}elsea=a*factorial(a-1);returna;}}voidAreaOfRect();voidvoidAreaOfRect();voidAreaOfTriangle();voidAreaOfRound();voidmain(){intprintf("0、退出\n1、長方形\n2、三角形\n3、圓形\n");if(select==0)return;switch(select){case1:AreaOfRect();break;//長方形case2AreaOfTrianglebreak;三角形case3:AreaOfRound();break;//圓形defaultprintf("0～4之間選擇。}}void{void{int

intprintf("面積為：%d\n",(x*printf("面積為：%d\n",(x*}

void{int} 中的參數(shù)為形式參數(shù)，函數(shù)調(diào)用時傳入的參voidvoidmain().... y1020.5 }}y(intnum,floatfraction)....函數(shù)形參和實 a取地址符inti=10;以上代碼片段會得到變量i的地址（指針＊指針運算符（間接運算符）