Creating a Function with For Loop and If Else

Hi I am supposed to create a function 'check_even' that accepts three arguments (1) ' df' a dataframe (2) ' col_test' to test if each row value in the indicated column is even or odd. Use for loop and nrow function. (3) ' col_multiply' the column to multiply by 2 if the 'col_test' is even and multiply by 3 if the 'col_test' is odd

• Store the result in a new column in the ' df' call ' res' and return the whole dataframe ' df'
• Test your function by running this code ' check_even(df_test, 'INT1', 'INT2')'

df_test = data.frame(INT1 = c(1:10), INT2 = (sample(x = c(20:100),size = 10, replace = F)))
df_test

check_even = function(df, col_test, col_multiply){
  for(i in 1:nrow(df)){
    if((df[,col_test[i]] %% 2) == 0){
      df[,'res'] = (df[,col_multiply[i]] * 2)
      
    } else 
      {
        df[,'res'] = (df[,col_multiply[i]] * 3)
        
        } 
    return(df) }
}  

 
check_even(df_test, 'INT1', 'INT2')

I keep getting a result of all the values multiply by 3. Can I seek some help to see what is wrong with my codes?