53 lines
1.3 KiB
Rust
53 lines
1.3 KiB
Rust
// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// Check that pure functions can modify local state.
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pure fn sums_to(v: ~[int], sum: int) -> bool {
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let mut i = 0u, sum0 = 0;
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while i < v.len() {
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sum0 += v[i];
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i += 1u;
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}
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return sum0 == sum;
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}
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pure fn sums_to_using_uniq(v: ~[int], sum: int) -> bool {
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let mut i = 0u, sum0 = ~mut 0;
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while i < v.len() {
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*sum0 += v[i];
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i += 1u;
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}
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return *sum0 == sum;
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}
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pure fn sums_to_using_rec(v: ~[int], sum: int) -> bool {
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let mut i = 0u, sum0 = F {f: 0};
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while i < v.len() {
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sum0.f += v[i];
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i += 1u;
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}
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return sum0.f == sum;
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}
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struct F<T> { f: T }
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pure fn sums_to_using_uniq_rec(v: ~[int], sum: int) -> bool {
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let mut i = 0u, sum0 = F {f: ~mut 0};
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while i < v.len() {
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*sum0.f += v[i];
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i += 1u;
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}
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return *sum0.f == sum;
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}
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pub fn main() {
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}
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