1. Statements and flow control
Iteration statements (loops)
We have already seen most of these:
While loops:
void ouch(int n) {
int x = 1;
while (x <= n)
{ printf("n = %d x = %d\n",n,x);
printf("Ouch! Stop it!!\n");
x++; } }
We could have also written this command as:
void ouch(int n) {
int x = 1; do
{ printf("n = %d x = %d\n",n,x);
printf("Ouch! Stop it!!\n");
x++;
} while (x <= n); }
What’s the difference???

2. Statements and flow control
The while command is an entry-condition loop; the do-while command is an exit-condition loop.
For loops:
int expo(int b, int p) {
int result = 1, passno;
for (passno = 1; passno <= p; passno++)
result = result * b;
return (result); }
Nested For loops:
#include "stdafx.h"
void main() {
int i, j, pp2array[4][2] = {{2,4},{3,9},{5,25},{7,49}};
for (i=0; i<4; i++)
for (j=0; j<2; j++)
printf("%d ", pp2array[i][j]);
printf("\n"); }

3. Statements and flow control
The output of the nested loop should appear as:

4. Statements and flow control
If - Else Statements
Consider a simple if statement:
if(1 == 1) { //Stuff to do if the condition is true (which in this case, it always is! 1 is always 1!) }
If else statement (enter, compile and run this code):
int main()
{ int input = 1;
char instring[5];
while (input != 0)
{ cout << "\nEnter an integer (enter 0 to quit): ";
cin >> instring;
input = atoi(instring);
if (input == 0)
return(1);
else if (input % 2 == 0)
cout << endl <<"The integer is even"<< endl;
else if (input % 2 == 1)
cout << endl <<"The integer is odd"<< endl; }

5. Statements and flow control
The output should appear as:

6. Statements and flow control
Rewrite (compile and Execute) your program so it appears as:
#include "stdafx.h"
#include <iostream>
using namespace std;
int main()
{ int input = 1, modinput;
char instring[5];
while (input != 0)
{ cout << "\nEnter an integer (enter 0 to quit): ";
cin >> instring;
input = atoi(instring);
if (input == 0)
return 0;
modinput = input % 2;
switch(modinput)
{ case 0: cout << "The Number is even" << endl; break;
case 1: cout << "The Number is odd" << endl; break; }