Consider the following C++ program. Assume that all the function calls are indep

Question

Consider the following C++ program. Assume that all the function calls are independent that is no function call affects other functions’ calls for each of the parameter passing method. void swap(int a, int b){ int temp = a; a = b; b = temp; } int main(){ int value = 2, list[5] = {1, 3, 5, 7, 9}; swap(value, list[0]); swap(list[0], list[1]); swap(value, list[value]); } What are the values of the variables value and list after each of the three calls to swap for each of the following parameter-passing methods? a) Pass-by-value: swap(value, list[0]) swap(list[0], list[1]) swap(value, list[value]) b) Pass-by-reference: swap(value, list[0]) swap(list[0], list[1]) swap(value, list[value]) c) Pass-by-value-reference: swap(value, list[0]) swap(list[0],list[1]) swap(value, list[value])

Explanation / Answer

void swap(int a, int b){
   int temp = a;
   a = b;
   b = temp;
}

int main(){
   int value = 2,
   list[5] = {1, 3, 5, 7, 9};
  
   swap(value, list[0]);
  
   swap(list[0], list[1]);
  
   swap(value, list[value]);
  
}

What are the values of the variables value and list after each of the three calls to swap for each of the following parameter-passing methods?

a) Pass-by-value: // No change in original list and variable value
   swap(value, list[0]) :
       value = 2
       list : {1, 3, 5, 7, 9}
  
   swap(list[0], list[1])
       value = 2
       list : {1, 3, 5, 7, 9}
  
   swap(value, list[value])
       value = 2
       list : {1, 3, 5, 7, 9}
  

b) Pass-by-reference:
   swap(value, list[0])
       value = 1
       list : {2, 3, 5, 7, 9}
  
   swap(list[0], list[1])
       value = 2
       list : {3, 1, 5, 7, 9}
  
   swap(value, list[value])
       value = 5
       list : {1, 3, 2, 7, 9}

c) Pass-by-value-reference:
   swap(value, list[0])
       value = 1
       list : {2, 3, 5, 7, 9}
  
   swap(list[0],list[1])
       value = 2
       list : {3 1, 5, 7, 9}
  
   swap(value, list[value])
       value = 5
       list : {1, 3, 2, 7, 9}

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