2011. Final Value of Variable After Performing Operations

There is a programming language with only four operations and one variable `X`:

• `++X` and `X++` increments the value of the variable `X` by `1`.
• `--X` and `X--` decrements the value of the variable `X` by `1`.

Initially, the value of `X` is `0`.

Given an array of strings `operations` containing a list of operations, return the final value of `X` after performing all the operations.

Example 1:

```Input: operations = ["--X","X++","X++"]
Output: 1
Explanation: The operations are performed as follows:
Initially, X = 0.
--X: X is decremented by 1, X =  0 - 1 = -1.
X++: X is incremented by 1, X = -1 + 1 =  0.
X++: X is incremented by 1, X =  0 + 1 =  1.
```

Example 2:

```Input: operations = ["++X","++X","X++"]
Output: 3
Explanation: The operations are performed as follows:
Initially, X = 0.
++X: X is incremented by 1, X = 0 + 1 = 1.
++X: X is incremented by 1, X = 1 + 1 = 2.
X++: X is incremented by 1, X = 2 + 1 = 3.
```

Example 3:

```Input: operations = ["X++","++X","--X","X--"]
Output: 0
Explanation: The operations are performed as follows:
Initially, X = 0.
X++: X is incremented by 1, X = 0 + 1 = 1.
++X: X is incremented by 1, X = 1 + 1 = 2.
--X: X is decremented by 1, X = 2 - 1 = 1.
X--: X is decremented by 1, X = 1 - 1 = 0.
```

Constraints:

• `1 <= operations.length <= 100`
• `operations[i]` will be either `"++X"`, `"X++"`, `"--X"`, or `"X--"`.

2011. Final Value of Variable After Performing Operations
``````struct Solution;

impl Solution {
fn final_value_after_operations(operations: Vec<String>) -> i32 {
let mut res = 0;
for op in operations {
if op.contains('+') {
res += 1;
} else {
res -= 1;
}
}
res
}
}

#[test]
fn test() {
let operations = vec_string!["--X", "X++", "X++"];
let res = 1;
assert_eq!(Solution::final_value_after_operations(operations), res);
let operations = vec_string!["++X", "++X", "X++"];
let res = 3;
assert_eq!(Solution::final_value_after_operations(operations), res);
let operations = vec_string!["X++", "++X", "--X", "X--"];
let res = 0;
assert_eq!(Solution::final_value_after_operations(operations), res);
}
``````