V信公众号：  程序员架构笔记

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1. 条件语句

if 语句

if 语句用于根据条件执行代码块。如果条件为真，则执行 if 块中的代码。

int x = 10;
if (x > 5) {
    std::cout << "x is greater than 5" << std::endl;
}

else if 语句

else if 语句用于在 if 条件不满足时检查另一个条件。

int x = 10;
if (x > 20) {
    std::cout << "x is greater than 20" << std::endl;
} else if (x > 5) {
    std::cout << "x is greater than 5 but less than or equal to 20" << std::endl;
}

else 语句

else 语句用于在 if 和 else if 条件都不满足时执行代码块。

int x = 3;
if (x > 20) {
    std::cout << "x is greater than 20" << std::endl;
} else if (x > 5) {
    std::cout << "x is greater than 5 but less than or equal to 20" << std::endl;
} else {
    std::cout << "x is 5 or less" << std::endl;
}

switch 语句

switch 语句用于根据变量的值执行不同的代码块。

int x = 2;
switch (x) {
    case 1:
        std::cout << "x is 1" << std::endl;
        break;
    case 2:
        std::cout << "x is 2" << std::endl;
        break;
    default:
        std::cout << "x is not 1 or 2" << std::endl;
        break;
}

2. 循环语句

for 循环

for 循环用于重复执行代码块，通常用于已知循环次数的情况。

for (int i = 0; i < 5; i++) {
    std::cout << "i is " << i << std::endl;
}

while 循环

while 循环用于在条件为真时重复执行代码块。

int i = 0;
while (i < 5) {
    std::cout << "i is " << i << std::endl;
    i++;
}

do-while 循环

do-while 循环与 while 循环类似，但它至少会执行一次代码块，然后再检查条件。

int i = 0;
do {
    std::cout << "i is " << i << std::endl;
    i++;
} while (i < 5);

3. 控制语句

break 语句

break 语句用于立即退出循环或 switch 语句。

for (int i = 0; i < 10; i++) {
    if (i == 5) {
        break;
    }
    std::cout << "i is " << i << std::endl;
}

continue 语句

continue 语句用于跳过当前循环的剩余部分，直接进入下一次循环。

for (int i = 0; i < 10; i++) {
    if (i % 2 == 0) {
        continue;
    }
    std::cout << "i is " << i << std::endl;
}

return 语句

return 语句用于从函数中返回值并退出函数。

int add(int a, int b) {
    return a + b;
}

int result = add(3, 4);
std::cout << "Result is " << result << std::endl;