打印一个菱形 唔 花了好长时间啊

#include<stdio.h>
#include<math.h>
int main(){
    int i,j,n;
    printf("n=");
    scanf("%d",&n);
    printf("\n");
    for (i=1;i<=2*n+1;i++){
    for (j=1;j<=(-abs(i-n-1)+2*n+1);j++){
        if (j<=abs(n+1-i))
        printf(" ");
        else
        printf("*");
    }
    printf("\n");
    }
    printf("This is a %d-decade lozenge/diamond.\n ",2*n+1);
    system("pause");
    
    return 0;
}

　　花了好长时间,

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