Pascal triangle （楊輝三角）製表符

Description:
By using two-dimensional array, write C program to display a table that represents a Pascal triangle of any size. In Pascal triangle, the first and the second rows are set to 1. Each element of the triangle (from the third row downward) is the sum of the element directly above it and the element to the left of the element directly above it. See the example Pascal triangle(size=5) below:

1
1 1
1 2 1
1 3 3 1
1 4 6 4 1

#include<stdio.h>
int a[101][101] = {0};
// 先初始化數組全爲0
void printPascalTr(int size) {
    printf("1\t\n");
    // 先打印第一行的1，不然會少一行超慘
    a[1][1] = 1;
    // 初始已知第一行第一列是1
    int i, j;
    // 下面用兩個for循環打表，外層控制行，內層控制列
    for (i = 2; i <= size; i++) {
        for (j = 1; j <= i; j++) {
            a[i][j] = a[i - 1][j] + a[i - 1][j - 1];
            // 這個數是它左上方和頭頂的和
            printf("%d\t", a[i][j]);
        }
        printf("\n");
        // 注意一行打完之後換行
    }
}
int main() {
    int size;
    printf("Enter Pascal triangle size:");
    scanf("%d", &size);
    printPascalTr(size);
    getchar();
    return 0;
}