初學(xué)C語言常用簡單程序代碼

-.z.初學(xué)C語言常用簡單程序代碼素?cái)?shù)的篩選#include<stdio.h>#include<math.h>#defineN1000intmain(intargc,char*argv[]){inti,j,num[N];for(i=0;i<N;i++)num[i]=i+1;for(i=1;i<(int)sqrt((double)N);i++){if(num[i]){for(j=i+1;j<N;j++){if(num[j])if(num[j]%num[i]==0)num[j]=0;}}}for(i=1;i<N;i++)if(num[i])printf("%d",num[i]);return0;}輸出時(shí)分秒#include<stdio.h>main(){ int*,s,t,d; scanf("%d",&*); s=*%60; t=(*/60)%60; d=(*/60)/60; printf("%d時(shí)%d分%d秒",d,t,s);}三個(gè)數(shù)的交換#include<stdio.h>voidmain(){ inta,b,c,t; scanf("%d%d%d",&a,&b,&c); printf("Theoriginalnumber:a=%d,b=%d,c=%d\n",a,b,c);t=a,a=b,b=t;t=a,a=c,c=t; printf("afterswap:a=%d,b=%d,c=%d",a,b,c);}switch語句的運(yùn)用#include<stdio.h>main(){ inta,m; printf("pleaseinputanumber:"); scanf("%d",&a); switch(a/10) { case10: case9:m=5;break; case8:m=4;break; case7:m=3;break; case6:m=2;break; default:m=1; } printf("m=%d",m);}判斷奇數(shù)和偶數(shù)#include<stdio.h>main(){ int*; printf("Pleaseinputanumber:"); scanf("%d",&*); if(*%2==0) printf("thisisaoushu!"); else printf("thisisajishu!");}小寫改大寫，假設(shè)是大寫則不變include<stdio.h>main(){charc1,c2;printf("Inputaletter\n");scanf("%c",&c1);c2=('a'<=c1&&c1<='z')"(c1-'a'+'A'):c1;printf("%c",c2);getchar();return0;}輸入一個(gè)數(shù)，輸出這個(gè)數(shù)是幾位數(shù)#include<stdio.h>main(){ int*,n; printf("pleaseinputanumber:"); scanf("%d",&*); n=0; while(*!=0) { *=*/10; n++; }printf("%d",n);}輸入一個(gè)數(shù)，判斷它是幾位數(shù)，然后逆序輸出#include<stdio.h>intmain(){intnum;intlen=0;inttemp=0;printf("Pleaseinputanumber:\n");scanf("%d",&num);while((num%10)!=0){temp=temp*10+(num%10);len++;num=num/10;}printf("length=%d\n",len);printf("Reverseis%d",temp);}打印水仙花數(shù)#include<stdio.h>main(){ int*,a,b,c; for(*=100;*<=999;*++) { a=*%10; b=(*/10)%10; c=*/100; if(*==a*a*a+b*b*b+c*c*c) { printf("%5d",*); } } printf("\n");}判斷閏年#include"stdio.h"main(){ intk,flag,n=0;for(k=1980;k<=2880;k++) { flag=(k%4==0)&&(k%100!=0)||(k%400==0); if(flag) {printf("%5d",k); n++; if(n%10==0) printf("\n"); } }printf("\n");}求1-3+5-7...-99+101的值#include<stdio.h>main(){ intsum,i,t; sum=1; t=1; for(i=3;i<=101;i=i+2){ t=-t; sum=sum+t*i; } printf("sum=%d",sum);}求前n項(xiàng)和#include<stdio.h>main(){ floats,t; intn,i,fz,fm;s=0; fz=2; fm=1; printf("Entern:"); scanf("%d",&n); for(i=1;i<=n;i++){ t=(1.0*fz)/fm; s=s+t;fz=fz+fm; fm=fz-fm; } printf("s=%f\n",s);}開發(fā)一個(gè)程序求全班學(xué)生*門課的平均成績，要求程序每次運(yùn)行時(shí)班級人數(shù)可為任意/*用標(biāo)記值來指示數(shù)據(jù)輸入的完畢*/#include<stdio.h>main(){ floataverage,total; intcounter,score; total=0.0; counter=0; printf("輸入成績,-1表示完畢:"); scanf("%d",&score); while(score!=-1)/*用-1表示輸入的完畢,同時(shí)循環(huán)輸入分?jǐn)?shù)*/ { total=total+score; counter++; printf("輸入下一個(gè)成績,-1表示輸入完畢:"); scanf("%d",&score); } if(counter!=0) { average=total/counter; printf("全班平均成績?yōu)椋?.2f\n",average); } else printf("沒有輸入成績\n"); return0;}求二元一次方程的根#include<stdio.h>#include<math.h>main(){ floata=4,b=-40,c=91; float*1,*2; floatdelta; delta=sqrt(b*b-4.0*a*c); *1=(-b+delta)/(2.0*a); *2=(-b-delta)/(2.0*a); printf("*1=%f*2=%f\n",*1,*2);}if語句的運(yùn)用#include<stdio.h>main(){ inta,b,c,s,w,t; s=w=t=0; a=-1; b=c=3; if(c>0) s=a+b; if(a<=0) { if(b>0) if(c<=0) w=a-b; } else if(c>0) w=a-b; else t=c; printf("s=%d,w=%d,t=%d",s,w,t);}輸入學(xué)生的生日，輸出他的實(shí)足年齡#include<stdio.h>main(){ inty0,m0,d0,y1,m1,d1,age; printf("\npleaseinputbirthday(yyyy/mm/dd):"); scanf("%d/%d/%d",&y0,&m0,&d0); printf("\npleaseinputcurrentday(yyyy/mm/dd):"); scanf("%d/%d/%d",&y1,&m1,&d1); if((m1>m0)||(m1=m0&&d1>=d0)) age=y1-y0; else age=y1-y0-1; printf("age=%d\n",age);}指針變量作為函數(shù)參數(shù)，實(shí)現(xiàn)兩數(shù)的交換#include<stdio.h>voidsswap(int**,int*y);main(){ inta=10,b=20; printf("beforeswap:a=%d,b=%d\n",a,b); sswap(&a,&b); printf("afterswap:a=%d,b=%d\n",a,b);}voidsswap(int**,int*y){ intt; t=**; **=*y; *y=t;}通過函數(shù)調(diào)用輸出兩個(gè)實(shí)型數(shù)中最大的一個(gè)#include<stdio.h>float*f(float*p*,float*py){ if(*p*>*py) returnp*; returnpy;}main(){ float*=10.0,y=20.0,*a=&*,*b=&y; printf("*a=%f,*b=%f,ma*=%f\n",*a,*b,*f(a,b));}計(jì)算并輸出一個(gè)數(shù)組中所有元素的和，最大值，最小值，值為奇數(shù)的元素個(gè)數(shù)編寫一個(gè)函數(shù)，將一個(gè)字符串中的字符全部轉(zhuǎn)成大寫#include<stdio.h>voidLower2Upper(char*str){ char*p=str; while(*p!=0) { if(*p<='z'&&*p>='a') *p=*p-32; p++; }}main(){ chars[10]="Hello!"; inti; Lower2Upper(s); for(i=0;i<10;i++) printf("%c",s[i]);}計(jì)算一個(gè)字符在一個(gè)字符串中出現(xiàn)的次數(shù)#include<stdio.h>intcount(charch,char*str){ char*p=str; intnum=0; while(*p!='\0') if(*p++==ch) num++;returnnum;}main(){ charah='a'; chars[]="haowareayou";printf("thenumberis:"); printf("%d\n",count('a',s));}刪除一維數(shù)組中所有一樣的數(shù)#include<stdio.h>voidunique(int*a,int*n){ intk=1; inti,m; m=a[0]; for(i=0;i<*n;i++) { if(a[i]>m) { a[k++]=a[i]; m=a[i]; } } *n=k;}main(){ inta[10]; intn=10,i; printf("inputalistnumber:"); for(i=0;i<n;i++) scanf("%d",&a[i]); printf("Beforedelete:...\n"); for(i=0;i<n;i++) printf("%d",a[i]); unique(a,&n); printf("afterdelete....\n"); for(i=0;i<n;i++) printf("%d",a[i]); printf("\n");}將字符串按字典順序輸出#include<stdio.h>#include<string.h>#defineN5voidsort(char*name[],intn);voidprn(char*name[],intn);voidmain(){ char*name[]={"China","America","Australia","France","German"}; sort(name,N); prn(name,N);}voidsort(char*name[],intn){ char*pt; inti,j,k; for(i=0;i<n-1;i++) { k=i; for(j=i+1;j<n;j++) if(strcmp(name[k],name[j])>0) k=j; if(k!=i) { pt=name[i]; name[i]=name[k]; name[k]=pt; } }}voidprn(char*name[],intn){ int