# 原始for循环
vec <- c(1, 2, 3, 4, 5)
sum_of_squares <- 0
for (i in vec) {
  sum_of_squares <- sum_of_squares + i^2
}
print(sum_of_squares)

# 转换后的函数
calculate_sum_of_squares <- function(vec) {
  sum_of_squares <- 0
  for (i in vec) {
    sum_of_squares <- sum_of_squares + i^2
  }
  return(sum_of_squares)
}

# 调用函数
vec <- c(1, 2, 3, 4, 5)
result <- calculate_sum_of_squares(vec)
print(result)

calculate_sum_of_squares <- function(vec) {
  stopifnot(is.vector(vec))
  sum_of_squares <- 0
  for (i in vec) {
    sum_of_squares <- sum_of_squares + i^2
  }
  return(sum_of_squares)
}

# 使用向量化操作替代for循环
calculate_sum_of_squares <- function(vec) {
  return(sum(vec^2))
}