7.24 Learning notes nesting for loops, exhaustive iterations for loops

Nesting for loops
Enter a positive integer to find the factorial and

Nesting
Console.Write ("Please enter a positive integer:");
int a = Int. Parse (Console.ReadLine ());
int sum = 0;
for (int i = 1; i <= A; i++)
{
int jie = 1;
for (int j = 1; J <= I; j + +)
{
Jie *= J;
}
sum + = Jie;
}
Console.WriteLine ("The result is:" + sum);
Console.ReadLine ();
99 Table of formulas
for (int i = 1; I <= 9; i++)
{
for (int j = 1; J <= I; j + +)
{
Console.Write ("{0}*{1}={2}\t", j,i, (J*i));
}
Console.Write ("\ n");
}

Console.ReadLine ();

Triangle at right-hand corner
for (int i = 1; I <= 5; i++)
{
for (int j = 1; J <= 5-i; j + +)
{
Console.Write ("");
}
for (int j = 1; J <= I; j + +)
{
Console.Write ("-");
}
Console.WriteLine ();
}

Console.ReadLine ();

Types of problems that loops can solve
Exhaustive, go through all the possible situations, and use the IF condition to filter out conditions that satisfy the condition.

Unit to send a 150-dollar shopping card,
Take the supermarket to buy three kinds of cleaning supplies.
Shampoo 15 yuan, soap 2 yuan, toothbrush 5 yuan.
Just spend 150 yuan, how many kinds of buying method,
How do you buy every kind of buying method?
Shampoo x 10
Toothbrush y 30
Soap Z 75
int ci = 0;
int Biao = 0;
for (int x = 0; x <= × x + +)
{
for (int y = 0; y <=; y++)
{
for (int z = 0; z <=; z++)
{
ci++;
if (x + y * 5 + z * 2 = = 150)
{
biao++;
Console.WriteLine ("{0} Buy Method: Shampoo {1} bottle, toothbrush {2} branch, soap {3} block. ", Biao, X, Y, z);
}
}
}
}
Console.WriteLine ("There are a total of {0} buying methods.") ", Biao);
Console.WriteLine (CI);
Console.ReadLine ();

Iterative, from the initial situation according to the law and constantly solve the intermediate situation, the final derivation of the results.

paper can be folded in half, paper thickness of 0.07 mm.
            Q How many times can I fold at least 8848?
            Double height = 0.07;//8848m=8848000
            int ci = 0;
            while (height<=8848000)
             {
               ci++;
              height *= 2;//height=height*2;
           }
            Console.WriteLine (CI);
            console.readline ();

7.24 Learning notes nesting for loops, exhaustive iterations for loops