C语言程序：输出矩阵及其上下三角矩阵

#include <stdio.h>

int main() { int n, i, j; printf("Input n:"); scanf("%d", &n); int matrix[n][n];

printf("Input the elements of the matrix:\n");
for (i = 0; i < n; i++) {
    for (j = 0; j < n; j++) {
        scanf("%d", &matrix[i][j]);
    }
}

printf("The input matrix is:\n");
for (i = 0; i < n; i++) {
    for (j = 0; j < n; j++) {
        printf("%4d", matrix[i][j]);
    }
    printf("\n");
}

printf("The lower triangular matrix is:\n");
for (i = 0; i < n; i++) {
    for (j = 0; j <= n; j++) {
        if (i >= j)
            printf("%4d", matrix[i][j]);
        else
            printf("    ");
    }
    printf("\n");
}

printf("The upper triangular matrix is:\n");
for (i = 0; i < n; i++) {
    for (j = 0; j < n; j++) {
        if (i <= j)
            printf("%4d", matrix[i][j]);
        else
            printf("    ");
    }
    printf("\n");
}

return 0;

}