初识3

#include <math.h>
#include <stdio.h>
void solve(double a, double b, double c);
int main() {
double a, b, c;
printf("Enter a, b, c: ");
while(scanf("%lf%lf%lf", &a, &b, &c) != EOF) {
solve(a, b, c); 
printf("Enter a, b, c: ");
}
return 0;
}

void solve(double a, double b, double c) {
double x1, x2;
double delta, real, imag;
if(a == 0)
printf("not quadratic equation.\n");
else {
delta = b*b - 4*a*c;
if(delta >= 0) {
x1 = (-b + sqrt(delta)) / (2*a);
x2 = (-b - sqrt(delta)) / (2*a);
printf("x1 = %f, x2 = %f\n", x1, x2);
}
else {
real = -b/(2*a);
imag = sqrt(-delta) / (2*a);
printf("x1 = %f + %fi, x2 = %f - %fi\n", real, imag, real,
imag);
}
}
}

　　

任务二

#include <stdio.h>
long long fac(int n); 
int main() {
int i,n;
printf("Enter n: ");
scanf("%d", &n);
for(i=1; i<=n; ++i)
printf("%d! = %lld\n", i, fac(i));
return 0;
}
long long fac(int n) {
static long long p = 1;
p = p*n;
printf("p=%lld\n",p);
return p;
}

　　

#include<stdio.h>
int func(int, int);
int main() {
int k=4,m=1,p1,p2;
p1 = func(k,m) ;
p2 = func(k,m) ;
printf("%d,%d\n",p1,p2) ;
return 0;
}
int func(int a,int b) {
static int m=0,i=2;
i += m+1;
m = i+a+b;
return (m);
}

　　

static静态变量

任务三

#include<stdio.h>
#define N 1000
int fun (int n,int m,int bb[N]){
	int i,j,k=0,flag;
	for(j=n;j<=m;j++){
		int flag=1;
		for(i=2;i<j;i++)
		    if(j%i==0){
		    	flag=0;
				 
		    	break;
		    	
			}
		if(flag)
		   bb[k++]=j;
	}
	return k;
}
int main( ){
	int n=0,m=0,i,k,bb[N];
	scanf("%d",&n);
	scanf("%d",&m);
	for(i=0;i<m-n;i++)
	    bb[i]=0;
	k=fun(n,m,bb);
	for(i=0;i<k;i++)
	    printf("%4d",bb[i]);
	return 0;
}

　　

任务四

#include <stdio.h>
long long fun(int n); // 函数声明
int main() {
int n;
long long f;
while(scanf("%d", &n) != EOF) {
f = fun(n); // 函数调用
printf("n = %d, f = %lld\n", n, f);
}
return 0;
}



long long fun(int n){
if(n==1)
   return 1;
else
   return 2*fun(n-1)+1;
}

　　

任务五

#include <stdio.h>
void draw(int n, char symbol); // 函数声明
#include <stdio.h>
int main() {
int n, symbol;
while(scanf("%d %c", &n, &symbol) != EOF) {
draw(n, symbol); // 函数调用
printf("\n");
}
return 0;
}
void draw(int n,char symbol){
int line,i,j;
for(line=1;line<=n;line++){
	for(i=1;i<=n-line;i++)
	printf(" ");
	for(j=1;j<=2*line-1;j++)
	printf("%c",symbol);
	printf("\n");
}
}