Changing Char x to Char y in a Array.

Question

In the following code I am running into an issue with mutating an array. My question is why doesn't the funOne function mutate the array that I pass in?

#include <iostream>

void funOne(char *arr, char x, char y, int z);
void print(char *array);

void print(char *array){
std::cout << array << std::endl;
}

void funOne(char *arr, char x, char y, int z){
    z =  sizeof(arr);
    for(int i = 0; i<z; i++){
    if(arr[i] == x){
    x == y; 
    }

    }

}

int main(){

    char arra[] = {'a', 'b', 'a', 'b', 'a', 'b', 'a', 'b', 'a', 'b'};

    funOne(arra, 'a', 'c', 10);

    print(arra);



    system("pause");
    return 0;
}

Answer 1

x == y;

Whoops...?

• The == operator is for comparing things;
• The = operator is for assigning things.

Furthermore, I guess you wanted to assign to arr[i] , not x :

arr[i] = y;

Take greater care.

Your final problem is that z will be wrong, because arr is not your array but a pointer to your array… and sizeof(char*) is fixed. You will have to pass the array's length in to the function as another argument.

Or, y'know, use a std::vector seeing as this is the 21st century!!