#include <stdio.h>

main(){
    char c[15]={"Hello World!"};
    puts(c);
    
    int i;
    for(i=0;i<15;i++)
        printf("%c",c[i]);
    
    return 0;
}

数组符号请自行脑补，BUG修复中..

#include <stdio.h>

main(){
    int i,j,max,a3;
    for(i=0;i<3;i++){
        for(j=0;j<4;j++){
            scanf("%d",&ai);
            if(max<ai)
                max=ai;
        }
    }
    printf("max=%d",max);
}

#include <stdio.h>

int main(void){
    int year=0;

    scanf("%d",&year);
    if((year%4==0&&year%100!=0)||year%400==0)
        printf("%d is a leap year.",year);
    else
        printf("%d is not a leap year.",year);

    return 0;
}

#include <stdio.h>

int main(){
    int i, max, a[10];
    printf("Please type 10 Z numbers:n");
    for(i=0;i<10;i++){
        scanf("%d",&a[i]);
    }
    max=a[0];
    for(i=1;i<10;i++){
        if(max<a[i])
            max=a[i];
    }
    printf("max=%d",max);
    
    return 0;
}

#include <stdio.h>

int main(){
    int i,j,t,a[10];
    printf("Please type 10 Z numbers:n");
    for(i=0;i<10;i++){
        scanf("%d",&a[i]);
    }
    for(i=0;i<9;i++){
        for(j=0;j<9-i;j++){
            if(a[j]>a[j+1]){
                t=a[j];
                a[j]=a[j+1];
                a[j+1]=t;
            }
        }
    printf("从小到大排序为：n");
    for(i=0;i<10;i++){
        printf("%d t",a[i]);
        }
    }
}