090823c语言学习日记（第七章，分支和控制）

//使用break退出循环#include<stdio.h>int main(){ float length,width; printf("Enter the length:/n"); while(scanf("%f",&length)==1) { printf("Length=%.2f/n",length); printf("Enter the width:/n"); if(scanf("%f",&width)!=1) break; printf("Width=%.2f/n",width); printf("Area=%.3f/n",length*width); printf("Enter the length of the revtangle./n"); } printf("Done!/n"); getch(); return 0;}

//使用switch语句#include<stdio.h>#include<ctype.h>int main(){ char ch; printf("Give me a letter of the alphabet,and I will give."); printf("an animal name/nbeginning with that letter./n"); printf("Please type in a letter:type # to end my act./n"); while((ch=getchar())!='#') { if('/n'==ch) continue; if(islower(ch))//只是识别小写字母 switch(ch) { case 'a': printf(" argali,a wild sheep of Asia./n"); break;//跳到结尾处 case 'b': printf("babiruse,a wild pig of Malay./n"); break; case 'c': printf("coati,racoonlike mammal./n"); break; case 'd': printf("desman,aquatic,molelike critter/n"); break; default: printf("That is astumper!/n"); } else printf("I recognize only lowercase letters./n"); while(getchar()!='/n')//跳过输出的余下部分 continue; printf("Please type another letter or a #./n"); } printf("Bye"); getch(); return 0;}

//使用多重标签#include<stdio.h>int main(){ char ch; int a_ct,e_ct,i_ct,o_ct,u_ct; a_ct=e_ct=i_ct=o_ct=u_ct=0; printf("Enter some text:enter # to quit./n"); while((ch=getchar())!='#') {//在此，加上ch=toupper（ch)或是tolower（ch）， //前一个事小写返回大写，后一个正好相反 //则可以省下下面的多重标签。 switch(ch)//或是用switch（toupper（ch）），则ch的值不会改变。 { case 'a': case 'A': a_ct++; break; case 'e': case 'E': e_ct++; break; case 'i': case 'I': i_ct++; break; case 'o': case 'O': o_ct++; break; case 'u': case 'U': u_ct++; break; default:break; } } printf("number of vowels:A E I O U/n"); printf(" %2d %2d %2d %2d/n", a_ct,e_ct,i_ct,o_ct,u_ct); getch(); return 0;}

#include<stdio.h>int main(){ int i=0; while(i<3) { switch(i++){ case 0:printf("fat "); case 1:printf("hat "); case 2:printf("cat "); case 3:printf("Oh no!"); } putchar('/n'); } getch(); return 0;}

#include<stdio.h>int main(){ char ch; int c1=0; int c2=0; int c3=0; while((ch=getchar())!='#') { if(ch=='/n') c1++; else if(ch==' ') c2++; else c3++; } printf("The spaces are %d./n",c2); printf("The '/n' are %d and the other chars are %d./n",c1,c3); getch(); return 0;}

 

#include<stdio.h>int main(){ char ch; int c=1; while((ch=getchar())!='#') { putchar(ch); if((c++%8)==0) printf("/n"); } getch(); return 0;}

#include<stdio.h>int main(){ int num; int dnum=0;//偶数总数 int snum=0;//奇数总数 float s_dnum=0.0;//偶数和 float s_snum=0.0;//奇数和 printf("Please enter integers:/n"); while (scanf("%d",&num)==1&&num!=0) { if(num%2==0) { dnum++; s_dnum+=num; } else{ snum++; s_snum+=num; } } printf("The number of even are %d,The average is %.2f/n",dnum,s_dnum/dnum); printf("The number of odd number are %d,The average is %.2f/n",snum,s_snum/snum); getch(); return 0;}

#include<stdio.h>int main(){ char ch; int a=0; int b=0; printf("Please enter text:/n"); while((ch=getchar())!='#') { if(ch=='.') { ch='!'; a++; } else if(ch=='!') { ch='!!'; b++; } putchar(ch); } printf("%d,%d/n",a,b); getch(); return 0;}

//测量ei出现次数 #include<stdio.h>int main(){ char ch; char prev;//前一个字符。 int c=0; int n,m; while((ch=getchar())!='#') { n++; if(ch=='e') { m=n; prev='e'; continue; } if(prev=='e'&&ch=='i'&&m==n-1) c++; } printf("The times are %d./n",c); getch(); return 0;}

#include<stdio.h>int main(){ const float BASEPAY=10.00;//基本工资 const float TAX1=0.15;//前300美元的税率 const float TAX2=0.20;//300-450美元的税率 const float TAX3=0.25;//450以上的税率 const float BTIME=40.00;//基本上班时间 const float BTAX=300.00; const float BTAX2=150.00; float hours; float pay,tax; //定义工资，税 printf("Please enter workhours of a week(q to quit) :/n"); while(scanf("%f",&hours)==1) { if(hours<=BTIME)//上班时间小于40h { if((hours*BASEPAY)<=BTAX)//工资小于300 { pay=hours*BASEPAY; tax=pay*TAX1; printf("Pay=%.2f,tax=%.2f,pay-tax=%.2f/n",pay,tax,pay-tax); } else { pay=hours*BASEPAY; tax=BTAX*TAX1+(pay-BTAX)*TAX2; printf("Pay=%.2f,tax=%.2f,pay-tax=%.2f/n",pay,tax,pay-tax); } } else { hours=(hours-BTIME)*1.5+BTIME;//加班。超过40小时的部分为1.5倍时间 if((hours*BASEPAY)<=(BTAX+BTAX2)) { pay=hours*BASEPAY; tax=BTAX*TAX1+(pay-BTAX)*TAX2; printf("Pay=%.2f,tax=%.2f,pay-tax=%.2f/n",pay,tax,pay-tax); } else { pay=hours*BASEPAY; tax=BTAX*TAX1+BTAX2*TAX2+(pay-BTAX-BTAX2)*TAX3; printf("Pay=%.2f,tax=%.2f,pay-tax=%.2f/n",pay,tax,pay-tax); } } } getch(); return 0;}