------------恢复内容开始------------
// 一元二次方程求解
// 重复执行， 直到按Ctrl+D或Ctrl+E结束
//
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
int main() {
float a, b, c, x1, x2;
float delta, real, imag;
printf("Enter a, b, c: ");
while(scanf("%f%f%f", &a, &b, &c)) {
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);
}
}
printf("Enter a, b, c:\n");
}
system("pause");
return 0;
}
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int main() {
int guessNumber; // 存放程序运行时生成的1~100之间的随机整数
int ans; // 存放用户猜的数字
srand((time(0))); // 以时间函数作为随机种子
guessNumber = 1 + rand()%100; // 生成1~100之间的随机数
do {
printf("your guess number is(1~100): ");
scanf("%d", &ans);
if(ans < guessNumber)
printf("%d is lower than the number.\n", ans);
else if(ans > guessNumber)
printf("%d higher then the number.\n", ans);
}while(ans != guessNumber);
printf("Congratulations. you hit it~\n");
system("pause"); // 在devc中运行时，这一行可以去掉
return 0;
}
#include <stdio.h>
#include <stdlib.h>
int main() {
int number, max, min, n;
n=1;
printf("输入第%d个数: ", n);
scanf("%d", &number);
max = number;
min = number;
while(n < 5) {
n++;
printf("输入第%d个数: ", n);
scanf("%d", &number);
if(max < number)
max = number;
else if(min > number)
min = number;
}
printf("最大数为: %d\n", max);
printf("最小数为: %d\n", min);
system("pause");
return 0;
}
#include<stdio.h>
#include<math.h>
int isprime(int n);
int main()
{
int i;
int m;
m=0;
for(i=101;i<=200;i++)
{
if(isprime(i))
{
printf("%4d",i);
m++ ;
if(m%5==0)
printf("\n");
}
}
printf("\n");
printf("101~200之间共有%d个素数",m);
return 0;
}
int isprime(int n)
{
int k;
for(k=2;k<=sqrt(n);k++)
if(n%k==0)
return 0;
return 1;
}
#include<stdio.h>
#include <stdlib.h>
int main()
{
long s;
printf("Enter a number:");
int a,b=0,c=1;
scanf("%ld",&s);
while(s>0){
a=s%10;
s=s/10;
if(a%2!=0){
b=b+a*c;
c=c*10;
}
else
b=b+0;
}
printf("new number is :%d",b);
return 0;
}
原文：https://www.cnblogs.com/zhang654321/p/11894674.html