第二章

 

例题2-1

#include<stdio.h>
int main(void)
{
    printf("Hello World!\n");


    return 0;

}

例题2-2

#include<stdio.h>
int main(void)
{
    printf("Programming is fun.\n");
    printf("And programming in C is even more fun!\n");


    return 0;

}

#include<stdio.h>
int main(void)
{
    int celsius,fahr;


    fahr=100;
    celsius=5*(fahr-32)/9;


    printf("fahr=%d,celsius=%d\n",fahr,celsius);


    return 0;
}

 

例题2-4

 

 

例题2.5

#include<stdio.h>
#include<math.h>
int main(void)
{
    int money,year;
    double rate,sum;

    printf("Enter money:");
    scanf("%d",&money);
    printf("Enter year:");
    scanf("%d",&year);
    printf("Enter rate:");
    scanf("%lf",&rate);
    sum=money*pow(1+rate,year);
    printf("sum=%.2f\n",sum);

    return 0;
}

 

例题2-6

 

#include<stdio.h>
int main(void)
{
    int fahr,lower,upper;
    double celsius;

    printf("Enter lower:");
    scanf("%d",&lower);
    printf("Enter upper:");
    scanf("%d",&upper);
    printf("fahr  celsuis\n");

    for(fahr=lower;fahr<=upper;fahr++){
        celsius=(5.0/9.0)*(fahr-32);
        printf("%d%6.1f\n",fahr,celsius);
    }

    return 0;
}

 

 

例题2-4

 

#include<stdio.h>
int main(void)
{
    double x,y;

    printf("Enter x(x>=0):\n");

    scanf("%lf",&x);

    if(x<=15){
        y=4*x/3;
    }
    else{
       y=2.5*x-10.5;
    }
    printf("y=f(%f)=%.2f\n",x,y);


    return 0;
}

 

例题2-7

 

 

#include<stdio.h>
int main(void)
{
    int i,n,sum;

    printf("Enter n:");
    scanf("%d",&n);
    sum=0;
    for(i=1;i<=n;i++){
        sum=sum+i;
    }

    printf("Sum of numbers from 1 to %d is %d\n",n,sum);

    return 0;
}

 

例题2-9

 

#include<stdio.h>
int main(void)
{
    int i,n;
    double product;

    printf("Enter n:");
    scanf("%d",&n);
    product=1;
    for(i=1;i<=n;i++){
        product=product*i;
    }
    printf("product=%.0f\n",product);

    return 0;
}

 

例题2-10

 

 

#include<stdio.h>
#include<math.h>
int main(void)
{
    int i,n;
    double power;

    printf("Enter n:");
    scanf("%d",&n);
    for(i=0;i<=n;i++){
        power=pow(2,i);
        printf("pow(2,%d)=%.0f\n",i,power);
    }
    return 0;
}

 

 

例题2-11

 

 

#include<stdio.h>
double fact(int n);
int main(void)
{
    int i,n;
    double result;

    printf("Enter n:");
    scanf("%d",&n);
    for(i=0;i<=n;i++){
        result=fact(i);
        printf("%d!=%.0f\n",i,result);
    }

    return 0;
}


double fact(int n)
{
    int i;
    double product;

    product=1;
    for(i=1;i<=n;i++){
        product=product*i;
    }

    return product;
}