1、專升本計算機C語言程序設計:函數程序設計7.1.1 求Xn#include stdio.hdouble pow(double x,int n)/*函數的定義在main()之前時不需要聲明*/ double y; int i; y=1; if(n=0) return 1.0; else if(n0) for(i=1;i=n;i+) y=y*x; return y; else for(i=1;i=-n;i+) y=y*x; return 1/y; main()int x,y;printf(input x:);scanf(%d,&x);printf(input n:);scanf(%d,&y);pr

2、intf(result:%fn,pow(x,y);7.1.2 萬年歷#include main() int i,j,day,year,temp,temp_i; long int Year_days； long int sumdays(int year);/*函數定義在main()之后，在main()中要聲明*/ int IsLeapYear(int year);/*函數聲明的格式和定義函數時的頭一樣*/ int month_day=0,31,28,31,30,31,30,31,31,30,31,30,31,29,everyday614; /*此數組用來保存計算所得的日歷*/ printf(Pl

3、ease enter the year: ); scanf(%d,&year); Year_days=sumdays(year); /*調用函數sumdays()計算天數，year是實在參數*/ for( temp=1; temp=6; temp+ ) /*分6次輸出12個月的日歷*/ for(i=0;i6;i+) for(j=0;j14;j+) everydayij=0; switch(temp) /*一行輸出二個月份*/ case 1: printf(tJanuary %dtt February %dn,year,year);break; case 2: printf(tMarch %dt

4、t April %dn,year,year);break; case 3: printf(tMay %dtt June %dn,year,year);break; case 4: printf(tJuly %dtt August %dn,year,year);break; case 5: printf(tSeptember %dtt October %dn,year,year);break; case 6: printf(tNovember %dtt December %dn,year,year);break; printf(Mon Tue Wed Thu Fri Sat Sun Mon Tu

5、e Wed Thu Fri Sat Sunn); i=j=0; for( temp_i=0; temp_i(Year_days % 7); temp_i+) /*初始化數組*/ everyday0j+=0; day = 1; while(day=month_day2*temp-1) /*把奇數月的日歷輸入數組*/ if(j%7=0) j=0,i+; everydayij+=day; Year_days+; day+; i=0,j=7; for( temp_i = 0; temp_i (Year_days % 7); temp_i+) /*初始化數組*/ everyday0j+=0; day=1

6、; if( IsLeapYear(year) & 2*temp = 2) /*調用函數判斷是否是閏年*/ while( day = month_day13 ) /*把閏年偶數月的日歷輸入數組*/ if(j%14=0)j=7,i+; everydayij+=day; Year_days+; day+; else while(day=month_day2*temp) /*把偶數月的日歷輸入數組*/ if(j%14=0) j=7,i+; everydayij+=day; Year_days+; day+; for(i=0;i6;i+) /*輸出存儲在數組中的日期 */ for(j=0;j14;j+)

7、 if(everydayij!=0) printf(%-4d,everydayij); else printf( ); if(j=6) printf( ); printf(n); if( getch()=q) exit(0); getch();int IsLeapYear( int year ) /*定義函數IsLeapYear()用來判斷是否是閏年*/ if(year %4 = 0) & (year % 100 != 0) | (year % 400 = 0) ) return 1; else return 0;long int sumdays(int year) /*定義函數sumdays

8、()計算輸入年份之前的天數*/ int year_start=1,leapsum=0; while(year_startyear) if(IsLeapYear(year_start) /*調用函數IsLeapYear()判斷是否是閏年*/ leapsum+; year_start+; return 366*leapsum + 365*(year-leapsum);7.1.3 四則運算練習#include long int a,b,c,d,x,y,z; /*定義全局變量，*/char op;main() int f1(),f2(); /*函數聲明，無參函數*/ printf(Please inp

9、ut two data for example b/a,d/c:n); scanf(%ld/%ld%c%ld/%ld,&b,&a,&op,&d,&c); if(a=0|c=0) exit(0); f1(); /*函數調用*/ f2(); printf(%ld/%ld%c%ld/%ld = %ld/%ld,b,a,op,d,c,y,x);int f1() /*定義無參函數，但函數對全局變量進行操作*/ /*本函數無返回值，值已保存到全局變量中*/ if(op=+) y=b*c+d*a;x=a*c; if(op=-) y=b*c-d*a;x=a*c; if(op=*) y=b*d;x=a*c; i

10、f(op=/) y=b*c;x=a*d;int f2() /*和上一個函數一樣為無參函數，但函數對全局變量進行操作*/ /*本函數無返回值，值已保存到全局變量中*/ int i; /*函數的局部變量，盡在本函數內有效*/ z=x; if(xy) z=y; i=z; while(i1) if(x%i=0&y%i=0) x=x/i;y=y/i;continue; i-; 7.2.1 求最小值#include main() int x,y,z,min; int mintwo(int,int),minthree(int,int,int); printf(nPlease input three inte

11、rgers:); scanf(%d %d %d,&x,&y,&z); min=minthree(x,y,z);/*函數調用，傳入三個實參*/ printf(Min is %d,min); getch();int mintwo(int a, int b) /*函數定義*/ return(ab?a:b); /*使用條件語句，并將計算結果返回*/int minthree(int a,int b,int c) int z; z=mintwo(a,b); /*函數內嵌套調用函數mintwo()*/ z=mintwo(z,c); return(z);7.2.2 奇偶函數調用#include main()f

12、loat even(),odd(),dcall(); /*聲明需調用的函數*/float sum;int n;printf(nPlease input a interger:);while (1) /*判斷用戶輸入的數據是否大于1*/ scanf(%d,&n); if(n1) break;sum=(n%2=0)? dcall(even,n):dcall(odd,n); /*判斷是奇還是偶， 并調用對應的函數*/if(n%2=0)printf(Even=%f,sum);elseprintf(Odd=%f,sum);getch();float even(int n)float s=0;int i;

13、for(i=2;i=n;i+=2)s+=1.0/i;return(s);float odd(int n)float s=0;int i;for(i=1;i=n;i+=2)s+=1.0/i;return(s);float dcall(float (*fp)(),int n) float s; s=(*fp)(n); /*函數的嵌套調用，用指針實現多函數的調用*/ return(s);7.2.3 求階乘倒數之和#include main() long int rfact(int n); /*遞歸函數的聲明*/ long int n,i; float e=0,p; printf(Please inp

14、ut a integer:); scanf(%ld,&n); for(i=1;i=n;i+) p=rfact(i); /*函數調用*/ e=e+1.0/p; /*求和*/ printf(sum=%15.12fn,e); getch();long int rfact(int n) /*遞歸函數定義*/ if(n0) /*數據判斷*/ printf(Negative argument!n); exit(-1); /*正常退出*/ else if(n=0) /*遞歸的終點*/ return(1); else return n*rfact(n-1); /*遞歸調用*/7.2.4 漢諾塔#include

15、 main() int m; void hanoi(int n,char a, char b, char c); printf(Input the number of diskes:); scanf(%d,&m); printf(The step to moving %3d diskes:,m); hanoi(m,a,b,c); getch();void hanoi(int n,char a, char b, char c) if(n=1) printf(%c-%ct,a,c); else hanoi(n-1,a,c,b); /*第一次遞歸函數的調用*/ printf(%c-%cn,a,c);

16、 hanoi(n-1,b,a,c); /*第二次遞歸函數的調用*/ 7.3.1 三角函數使用# include # include main() void stringcpy(char a,char b,int x,int y); char ch18,ch24,ch33; int i,j=0; double (*f)(); printf(nInput sin(x) or cos(x) or tan(x):); scanf(%s,ch1); stringcpy(ch1,ch2,0,2); stringcpy(ch1,ch3,4,5); for(i=0;i=strlen(ch3)-1;i+) j=

17、j*10+(ch3i-0); if(!strcmp(ch2,sin) f=sin; else if(!strcmp(ch2,cos) f=cos; else if(!strcmp(ch2,tan) f=tan; else printf(Input errorn); exit(-1); printf(n%s(%d)=%8.3fn,ch2,j,(*f)(3.1415*j/180);void stringcpy(char a,char b,int x,int y) /*定義用于分離數據的函數*/ int i,j=0; for(i=x;i=y;i+) bj=ai; j+; bj=0;7.3.2 系統鼠

18、標檢查#include/*包含printf()庫函數*/#include/*包含exit()、getenv()庫函數*/#include/*包含strcmp()庫函數*/main() char *p; if(p=getenv(MOUSE)!=NULL) /*調用getenv()讀取系統環境變量*/ if(!strcmp(p,YES) printf(Mouse is OKn); else printf(n No mouse); getch();7.3.3 機器信息顯示#include stdio.h#include stdlib.h #include ctype.h#include conio.h main() void checksys(char); char ch; do printf(A: display directory