等差数列计算(by go)

package APfunc AnInt(a1, d, n int) int {return a1 + (n-1)*d}func AnFloat32(a1, d float32, n int) float32 {return a1 + float32(n-1)*d}func AnFloat64(a1, d float64, n int) float64 {return a1 + float64(n-1)*d}

package APfunc SumInt(a1, an, n int) int {return n * (a1 + an) / 2}func StraightSumInt(a1,d,n int) int{return n*a1 + n*(n-1)*d/2}func StraightSumFloat32(a1,d float32,n int) float32{n1 := float32(n)return n1*a1 + n1*(n1-1)*d/2}func StraightSumFloat64(a1,d float64,n int) float64{n1 := float64(n)return n1*a1 + n1*(n1-1)*d/2}func SumFloat64(a1, an float64, n int) float64 {return float64(n) * (a1 + an) / 2}func SumFloat32(a1, an float32, n int) float32 {return float32(n) * (a1 + an) / 2}