### Common Datatypes

This page contains the definitions of data types used throughout the blog.

The `float4` structure encapsulates 4 `float` values and can be used to represent a 4-element vector or a row of a 4-column matrix:
```struct float4
{
float4() {};
float4(float s) : x(s), y(s), z(s), w(s) {}
float4(float x, float y, float z, float w) : x(x), y(y), z(z), w(w) {}
float x, y, z, w;

inline float4 operator*(float s) const { return float4(x*s, y*s, z*s, w*s); }
inline float4 operator+(const float4& a) const { return float4(x+a.x, y+a.y, z+a.z, w+a.w); }
};

// dot product of two float4 vectors
inline float dot(const float4& a, const float4& b) {
return a.x * b.x + a.y * b.y + a.z * b.z + a.w * b.w;
}
```
Similar to the `float4` datatype, we define another common type: `float3`. It can be used, for example, for representing 3D vectors.
```struct float3
{
float3() {};
float3(float s) : x(s), y(s), z(s) {}
float3(float x, float y, float z) : x(x), y(y), z(z) {}
float x, y, z;

inline float3 operator*(float s) const { return float3(x*s, y*s, z*s); }
inline float3 operator+(const float3& a) const { return float3(x+a.x, y+a.y, z+a.z); }
};

// dot product of two float3 vectors
inline float dot(const float3& a, const float3& b) {
return a.x * b.x + a.y * b.y + a.z * b.z;
}
```
The `float2` datatype contains 2 float elements:
```struct float3
{
float2() {};
float2(float s) : x(s), y(s) {}
float2(float x, float y) : x(x), y(y) {}
float x, y;
};
```