C/C ++ knowledge points 4-printf function and cout calculation sequence, printfcout

C/C ++ knowledge points 4-printf function and cout calculation sequence, printfcout

Calculation sequence of the printf function: First press the stack from right to left, then the stack from left to right.

Routine:

#include"stdio.h"int main(){int arr[] = { 1, 2, 3, 4, 5 };int *ptr = arr;printf("%d %d\n", *ptr, *(++ptr));return 0;}

Output: 2, 2

Computing sequence: Calculate * (++ ptr), press the stack, then calculate * (ptr), and then press the stack.

Note: The calculation sequence of ++ ptr and ptr ++ may lead to different results.

#include"stdio.h"int main(){int arr[] = { 1, 2, 3, 4, 5 };int *ptr = arr;printf("%d %d\n", *ptr, *(ptr++));return 0;}

Output: 2, 1

Computing sequence: First press the stack * (ptr), then execute the ++ operation, and then press the stack * (ptr). During output, the stack is output from left to right, so the result is 2, 1.

The same is true for cout.

See routine:

#include"iostream"using namespace std;int main(){int arr[] = { 1, 2, 3, 4, 5 };int *ptr = arr;cout << *(ptr) << " " << *(ptr++) << " "<<*(ptr++)<<endl;return 0;}

Output: