c語言初學(xué)必背代碼

1、printf("sum=%dn",sum);/1.成績判斷#include<stdio.h>intmain()/成績intscore;printf("請輸入你的成績:n");scanf("%d",&score);/判斷if(score>=0&&score<60)printf("不及格n");elseif(60<=score&&score<80)printf("中等n");elseif(80<=score&&

2、amp;score<100)printf("優(yōu)秀n");elseprintf("輸入錯誤!n");/3.最大公約數(shù)#include<stdio.h>/求m,n的最大公約數(shù)intmain()intm,n;inti,k;printf("請輸入兩個數(shù):");scanf("%d%d",&m,&n);/三元運算符找較小的那個k=m<n?m:n;/從較小的那個數(shù)倒著往前找for(i=k;i>=1;i-)/這是公約數(shù)if(m%i=0)&&(n%i=0)printf(&

3、quot;最大公約數(shù)是%dn",i);break;/跳出for循環(huán)/4.最小公倍數(shù)/2.計算1到100的和#include<stdio.h>intmain()intsum=0;/存結(jié)果變量inti;for(i=1;i<=100;i+)sum=sum+i;#include<stdio.h>/求m,n的最小公倍數(shù)intmain()intm,n;intmax,min;/m,n中較大,較小的那個intk;/max,2*max,3*max,printf("請輸入兩個數(shù):");scanf("%d%d",&m,&

4、n);/也可以交換m,n,保證m小n大max=m>n?m:n;min=m<n?m:n;k=max;/從max開始while(k%min!=0)k+=max;/每次倍增printf("最小公倍數(shù)是%dn",k);/5.金字塔#include<stdio.h>/金字塔intmain()inti;/外層intj;/內(nèi)層for(i=1;i<=10;i+)/當前是在第i行/先補空格10-i個for(j=1;j<=10-i;j+)printf("");/再打2i-1個*for(j=1;j<=2*i-1;j+)printf(&

5、quot;*");printf("n");/6.九九乘法表#include<stdio.h>/打印九九乘法表intmain()inti,j;for(i=1;i<=9;i+)/外層一定是9行for(j=1;j<=i;j+)/內(nèi)層第幾行走幾遍printf("%d*%d=%d",i,j,i*j);printf("n");/7.百錢買百雞#include<stdio.h>/*百錢買百雞,類似1,2,5湊100銀幣問題*/intmain2()inti,j;/公雞，母雞個數(shù)for(i=0;i<=

6、20;i+)/公雞for(j=0;j<=33;j+)/母雞if(15*i+9*j+(100-i-j)=300)printf("公雞”母雞,小雞肝,i,j,100-i-j);sum+=ai;/1,2,5湊100銀幣問題intmain3()intcount=0;/情況數(shù)inti,j;/5分個數(shù)，2分個數(shù)for(i=0;i<=20;i+)/5分個數(shù)for(j=0;j<=50;j+)/2分個數(shù)if(5*i+2*j)<=100)count+;printf("%d:5分dj,2分個，1分djn",count,i,j,100-5*i-2*j);/8.一維

7、數(shù)組的最大值、最小值、平均值#include<stdio.h>#defineN10/宏定義常量intmain()inti;/下標索引intmax,min;doublesum=0;/累加和intaN=58,58,96,100,25,55,66,88,99,77;max=a0;/假設(shè)第一個最大min=a0;/假設(shè)第一個最小for(i=1;i<N;i+)if(ai>max)/比最大值還大max=ai;/你才是最大if(ai<min)/比最小值還小min=ai;/你才是最小printf("max=%d,min=%dn",max,min);printf(

8、"average=%.2lfn",sum/N);/9.二維數(shù)組的最大值、最小值、平均值#include<stdio.h>intmain()inti;/第幾行intj;/第幾列inta34=1,2,3,4,5,-6,7,8,9,19,39,0;intmax=a00;/假設(shè)你最大intmin=a00;/假設(shè)你最小doubleaverage;/平均值doublesum=0;/總和for(i=0;i<3;i+)/必定3行for(j=0;j<4;j+)/必定4列printf("%5d",aij);sum+=aij;if(aij>max

9、)max=aij;if(aij<min)min=aij;printf("n");average=sum/(3*4);printf("max=%d,min=%d,avg=%.2lfn",max,min,average);#include<stdio.h>/二維數(shù)組轉(zhuǎn)置：行變列，列變行intmain()inti;/第幾行intj;/第幾列inta34=1,2,3,4,5,-6,7,8,9,19,39,0;intb43;for(i=0;i<3;i+)for(j=0;j<4;j+)printf("%5d",aij

10、);printf("n");/矩陣轉(zhuǎn)置for(i=0;i<3;i+)for(j=0;j<4;j+)bji=aij;for(i=0;i<4;i+)for(j=0;j<3;j+)printf("%5d",bij);printf("n");#include<stdio.h>#defineN10/宏定義常量intmain()inti;/下標索引intj;inttmp;/臨時交換用intaN=58,58,96,100,25,55,66,88,99,77;/外層循環(huán)一定是N-1for(i=0;i<N-1;

11、i+)/兩兩交換，大的往后走for(j=0;j<N-i-1;j+)/交換if(aj>aj+1)tmp=aj;aj=aj+1;aj+1=tmp;for(i=0;i<N;i+)printf("%d",ai);printf("n");#include <stdio.h>/12.結(jié)構(gòu)冒泡排序/結(jié)構(gòu)定義,用戶自定義類型typedefstructstudentcharsno20;/學(xué)號charname20;/姓名intage;/年齡chargender;/性別chartel20;/電話;intmain()inti;intj;double

12、sum=0;structstudenttmp;/兩兩交換臨時用;/結(jié)構(gòu)數(shù)組structstudentteam5;for(i=0;i<5;i+)printf("請輸入第dj隊員的信息：n”,i+1);scanf("%s%s%d%c%s",teami.sno,,&teami.age,&teami.gender,teami.tel);/按年齡冒泡排序for(i=0;i<5;i+)for(j=0;j<5-i-1;j+)/兩兩交換if(teamj.age>teamj+1.age)tmp=teamj;teamj=te

13、amj+1;teamj+1=tmp;/取值printf("%-12s%-10s%-5s%-5s%-15sn","學(xué)號","姓名","年齡","性別","電話");for(i=0;i<5;i+)printf("%-12s%-10s%-5d%-5c%-15sn",teami.sno,,teami.age,teami.gender,teami.tel);/13.結(jié)構(gòu)數(shù)組找年齡最大值#include<stdio.h>/結(jié)構(gòu)定義

14、,用戶自定義類型typedefstructstudentcharsno20;/學(xué)號charname20;/姓名intage;/年齡chargender;/性別chartel20;/電話;intmain()inti;structstudenttmp;/找最大臨時用/結(jié)構(gòu)數(shù)組structstudentteam5;for(i=0;i<5;i+)printf("請輸入第%d個隊員的信息:n",i+1);scanf("%s%s%d%c%s",teami.sno,,&teami.age,&teami.gender,teami

15、.tel);/取值printf("%-12s%-10s%-5s%-5s%-15sn","學(xué)號","姓名","年齡","性別","電話");for(i=0;i<5;i+)printf("%-12s%-10s%-5d%-5c%-n",teami.sno,,teami.age,teami.gender,teami.tel);/找學(xué)號最大的那一個tmp=team0;for(i=1;i<5;i+)if(strcmp(teami.sno

16、,tmp.sno)>0)tmp=teami;printf("學(xué)號最大的隊員如下:n");printf("%-12s%-10s%-5d%-5c%-n",tmp.sno,,tmp.age,tmp.gender,tmp.tel);/14.文件讀寫#include<stdio.h>#include<stdlib.h>/結(jié)構(gòu)定義,用戶自定義類型typedefstructstudentcharsno20;/學(xué)號charname20;/姓名intage;/年齡chargender;/性別chartel20;/電話;/文件讀

17、寫intmain()structstudent*s,*p1;/個數(shù)未知FILE*fp;inti,n=0;charbuf1024;/fgets緩沖區(qū)/打開文件fp=fopen("e:test.txt","r");while(fgets(buf,1024,fp)!=NULL)n+;fclose(fp);/指向一個可以存儲n個student結(jié)構(gòu)的內(nèi)存空間s=(structstudent*)malloc(sizeof(structstudent)*n);p1=s;/不要動頭位置s的值/打開文件fp=fopen("e:test.txt",&qu

18、ot;r");for(i=0;i<n;i+)/從文件中讀入一行fscanf(fp,"%s%s%d%c%s",p1->sno,p1->name,&p1->age,&p1->gender,p1->tel);p1+;fclose(fp);p1=s;for(i=0;i<3;i+)printf("%s%s%d%c%sn",p1->sno,p1->name,p1->age,p1->gender,p1->tel);free(s);/15.輸入三角形三邊長計算周長和面積#i

19、nclude<stdio.h>#include<math.h>intmain()doublearea,perimeter,s,a,b,c;printf("請輸入三邊長abc:");scanf("%lf%lf%lf",&a,&b,&c);if(a+b>c)&&(a+c>b)&&(b+c>a)s=(a+b+c)/2;area=sqrt(s*(s-a)*(s-b)*(s-c);perimeter=a+b+c;n",area,perimeter);else

20、printf("三邊長無法構(gòu)成三角形。n");return0;/16.輸入年份和月份輸出對應(yīng)那一月的天數(shù)，要處理閏年#includeintmain()intyear,month;intleap=0;scanf("%d%d",&year,&month);if(year%4=0&&year%100!=0)|year%400=0)/閏年2月29天leap=1;switch(month)case1:case3:case5:case 7:case 8:case10:case12:printf("31");break;case4:case6:case9:case11:printf("30");break;case2:printf("%d",28+leap);break;default:printf("error");break;return0;/17.1，2，5分硬幣問題#include<stdio.h>intmain()intsum=0;for(inti=0;