实验4 函数和数组
#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); } } }
经过试验后发现一元二次方程的根可以设计成以函数返回值的方式返回给主调函数。
#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; 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); }
1. 理论结果为8,17,分析结果实验运行结果是否一致。
2. static变量特性:函数退出时,变量始终存在,但不能被其他函数使用,当再次进入该函数时,将保存上次的结果。
#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++) { flag=1; for(i=2;i<j;i++) if(j%i==0) { flag=0; break; } if(flag!=0) 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; }
#include <stdio.h> long long fun(int n); int main() { int n; long long f; while(scanf("%d", &n) != EOF) { f = fun(n); printf("n = %d, f = %lld\n", n, f); } return 0; } long long fun(int n) { int i; long long sum=1; for(i=0;i<n;i++) { sum*=2; } return (sum-1); }
#include <stdio.h> void draw(int n, char symbol); #include <stdio.h> int main() { int n, symbol; while(scanf("%d %c", &n, &symbol) != EOF) { draw(n, symbol); printf("\n"); } return 0; } void draw(int n, char symbol) { int i,j,line=1; while(line-n<=0) { for(i=0;i<n-line;i++) { printf(" "); } for(j=0;j<2*line-1;j++) { printf("%c",symbol); } printf("\n"); line++; } }
实习总结:啊啊啊啊都做出来真是太开心啦!!!!!!!!