实验3

#include<stdio.h>
int main()
{
    int c1,c2,c3,c4;
    scanf("%d%d",&c1,&c2);
    printf("%d\n",c1+c2);

    getchar();
    c3=getchar();
    c4=getchar();

    printf("%d\n",c3+c4);
    return 0;
}

#include<stdio.h>
int main()
{
    char c1,c2,c3,c4;
    scanf("%c%c",&c1,&c2);
    printf("%c%c\n",c1,c2);
    getchar();
    c3=getchar();
    c4=getchar();
    printf("%c %c\n",c3,c4);
    printf("%c %c %c %c\n",c1,c2,c3,c4);
    return 0;
}

#include<stdio.h>
int main()
{
    float R,S;
    printf("Enter R:");
    scanf("%f",&R);
    if(R>0){
        S=R*R*3.14;
        printf("S=%f\n",S);
    }
    else
        printf("输入错误");
    return 0;
}

#include<stdio.h>
int main()
{
    int i,n;
    double r,v,h;
    double cylinder(double r,double h);

    printf("enter n:");
    scanf("%d",&n);

    for(i=1;i<=n;i++){
        printf("Enter r and h:\n");
        scanf("%lf%lf",&r,&h);
        if((r<=0)||(h<=0)){
            printf("输入错误，重新输入");
        }
        else{
            v=cylinder(r,h);
            printf("V=%.3f\n",v);
        }
    }

    return 0;
}
double cylinder(double r,double h)
{
    double result;
    result=3.1415926*r*r*h;
    
    return result;
}