Work_1

#include <stdio.h>
#include <math.h>
#include <stdlib.h>
int main(){
    int x, i;
    int flag;
    int number = 0;
    printf("100~200之间的素数为：\n");
    for (x = 100; x <= 200; x++){
        flag = 1;
        for (i = 2; i < x; i++){
            if (x%i == 0){
            flag = 0;
            break;
            }
        }
        if (flag){
            printf("%5d", x);
            number++;
            if (number % 5 == 0)printf("\n");
        }
    }
    printf("\n");
    system("pause");
    return 0;
}

#include <stdio.h>
#include <math.h>
#include <stdlib.h>
int main(){
    int i, j;
    for (i = 1; i <= 9; i++)
    for (j = 1; j <= i; j++){
        printf("%2d*%2d=%2d  ", i, j, i*j);
        if (i == j)printf("\n");
    }
    printf("\n");
    system("pause");
    return 0;
}

int main(){
    int i, j = 0;
    printf("1000~2000的闰年为：\n");
    for (i = 1000; i <= 2000; i++){
        if ((i % 4 == 0 && i % 100 != 0) || i % 400 == 0){
            printf("%5d", i);
            j++;
            if (j % 10 == 0)printf("\n");
        }
    }
    printf("\n");
    system("pause");
    return 0;
}