选择结构程序代码参考

来源：互联网发布：软件售后工程师编辑：程序博客网时间：2024/05/16 08:45

这里写图片描述

*1，求y值*/#include <stdio.h>int main(){    float x,y;    printf("please input a number x=\n");    scanf("%f",&x);    if(x<1)    {        y=x;        printf("y=%5.2f\n",y);    }    else if(x>=10)    {        y=3*x-11;printf("y=%5.2f\n",y);    }    else     {        y=2*x-1;        printf("y=%5.2f\n",y);    }    return 0;}

/*2，输入三整数，由小到大输出*/#include <stdio.h>int main(){  int a,b,c;int t;  scanf("%d %d %d",&a,&b,&c);  if (a>b) {t=a;a=b;b=t;}  if(a>c)  { t=a; a=c; c=t; }  if(b>c)  { t=b; b=c; c=t;} printf("a=%d,b=%d,c=%d\n",a,b,c);}

/*3，判断任意三个数能否构成三角形，如果能求三角形面积*/#include<stdio.h>#include<math.h>int main(){    float a,b,c,s,area;    printf("please input any digital a b c\n");    scanf("%f,%f,%f",&a,&b,&c);    if(a+b>c)    {      s=(a+b+c)/2;      area=sqrt(s*(s-a)*(s-b)*(s-c));      printf("a=%f,b=%f,c=%f\narea=%7.1f",a,b,c,area);    }    else    printf("a,b,c不能构成三角形");     return 0;}

/*4，关于ax²+bx+c中a,b,c的讨论*/#include<stdio.h>#include<math.h>int main(){   float a,b,c,x,x1,x2,delta;  printf("plese input a b c three number\n");  scanf("%f,%f,%f",&a,&b,&c);  if(a==0)   {    if(b==0)    {     printf("it is not a quadratic equation\n");    }    else      {     x=-c/b;     printf("it is a linear equation\nx=%7.2f",x);      }  }  else  {    delta=b*b-4*a*c;    if(delta>=0)    {         x1=(-b+sqrt(delta))/(2*a);        x2=(-b-sqrt(delta))/(2*a);        printf("x1=%7.2f\nx2=%7.2f\n",x1,x2);    }    else    {        printf("no real root\n");    }     }   return 0;}

/*5，输入一个至多五位数，判断他的位数，并将此数倒叙：*/#include<stdio.h>#include<math.h>int main(){    int N,G,S,B,Q,W,P;    printf("please input a number(0-99999):\n");    scanf("%d",&N);    if(N>9999)    P=5;    else if(N>999)    P=4;    else if(N>99)    P=3;    else if(N>9)    P=2;    else P=1;    printf("place:%d\n",P);    W=N/10000;    Q=(int)(N-W*10000)/1000;    B=(int)(N-W*10000-Q*1000)/100;    S=(int)(N-W*10000-Q*1000-B*100)/10;     G=(int)(N-W*10000-Q*1000-B*100-S*10);    switch(P){        case(5):printf("the upside down number:");                printf("%d%d%d%d%d\n",G,S,B,Q,W);                break;        case(4):printf("the upside down number:");                printf("%d%d%d%d\n",G,S,B,Q);                break;        case(3):printf("the upside down number:");                printf("%d%d%d\n",G,S,B);                break;        case(2):printf("the upside down number:");                printf("%d%d\n",G,S);                break;        case(1):printf("the upside down number:");                printf("%d\n",G);                break;    }    return 0;}

/*6、编写程序，要求从键盘输入成绩，输出对应的等级（100分为A，90-99为A，80-89为B，70-79为C，60-69为D，小于60为E）。*/#include<stdio.h>int main(){       float score;    char grade;    printf("please input your score:");    scanf("%f",&score);    while(score>100||score<0)    {        printf("your score is error!\n");        scanf("%f",&score);    }    switch((int)(score/10))    {           case 10:        case 9:grade='A';break;        case 8:grade='B';break;        case 7:grade='C';break;        case 6:grade='D';break;        case 5:        case 4:        case 3:        case 2:        case 1:        case 0:grade='E';    }    printf("your score is:%7.2f\nyour level is:%c\n",score,grade);  return 0;  }

/*7、设计一个简单的计算机程序，用户输入运算数和四则运算符（+、-、*、/），输出计算结果。*/#include<stdio.h>#include<math.h>int main(){ double a,b; char c; scanf("%lf%c%lf",&a,&c,&b); switch(c) { case'+':printf("=%g",a+b);break; case'-':printf("=%g",a-b);break; case'*':printf("=%g",a*b);break; case'/':printf("=%g",a/b);break; } return 0;} ，

0 0