test:zig

guide/language/floats.zig

@@ -0,0 +1,39 @@
+const expect = @import("std").testing.expect;
+
+// Zig's floats are strictly IEEE-compliant unless `@setFloatMode(.Optimized)` is used,
+// which is equivalent to GCC's `-ffast-math`.
+// Floats coerce to larger float types.
+
+test "float widening" {
+    const a: f16 = 0;
+    const b: f32 = a;
+    const c: f128 = b;
+    try expect(c == @as(f128, a));
+}
+
+// Floats support multiple kinds of literal.
+
+const floating_point: f64 = 123.0E+77;
+const another_float: f64 = 123.0;
+const yet_another: f64 = 123.0e+77;
+
+const hex_floating_point: f64 = 0x103.70p-5;
+const another_hex_float: f64 = 0x103.70;
+const yet_another_hex_float: f64 = 0x103.70P-5;
+
+// Underscores may also be placed between digits.
+
+const lightspeed: f64 = 299_792_458.000_000;
+const nanosecond: f64 = 0.000_000_001;
+const more_hex: f64 = 0x1234_5678.9ABC_CDEFp-10;
+
+// Integers and floats may be converted using the built-in functions `@floatFromInt` and `@intFromFloat`.
+// `@floatFromInt` is always safe, whereas `@intFromFloat` is detectable illegal behaviour
+// if the float value cannot fit in the integer destination type.
+
+test "int-float conversion" {
+    const a: i32 = 0;
+    const b = @as(f32, @floatFromInt(a));
+    const c = @as(i32, @intFromFloat(b));
+    try expect(c == a);
+}