[C# 筆記] for 練習

求1-100之間的整數和、偶數和、奇數和

整數和

int sum = 0;
for (int i = 1; i <= 100; i++) {
    sum += i;
}
Console.WriteLine($"整數和: {sum}");

偶數和(改變遞增 i=2, i+=2)

i=2 從2開始，每次加2，2,4,6…

int sum = 0;
for (int i = 2; i <= 100; i+=2) { //i=2 從2開始，每次加2，2,4,6...
    sum += i;
}
Console.WriteLine($"偶數和: {sum}");

偶數和(mod計算%)

mod計算判斷: sum % 2 == 0

int sum = 0;
for (int i = 1; i <= 100; i++) {
    if (sum % 2 == 0) sum += i; //mod計算: sum % 2 == 0
}
Console.WriteLine($"偶數和: {sum}");

奇數和(改變遞增 i+=2)

i=1 從1開始，每次加2，1,3,5,7…

int sum = 0;
for (int i = 1; i <= 100; i += 2) { //i=1 從1開始，每次加2，1,3,5,7...
    sum += i;
}
Console.WriteLine($"奇數和: {sum}");

奇數和(mod計算%)

mod計算判斷: sum % 2 != 0

int sum = 0;
for (int i = 1; i <= 100; i++) {
    if (sum % 2 != 0) sum += i; //mod計算: sum % 2 != 0
}
Console.WriteLine($"奇數和: {sum}");