编程字符串变换怎么用的

在C语言中，可以使用一些内置函数和自定义函数来实现字符串的变换。以下是一些常见的字符串变换方法：

将字符串转换为大写

```c

include

include

include

void to_upper(char *str) {

for (int i = 0; str[i]; i++) {

str[i] = toupper(str[i]);

}

}

int main() {

char str[] = "hello world";

to_upper(str);

printf("%s\n", str);

return 0;

}

```

将字符串转换为小写

```c

include

include

include

void to_lower(char *str) {

for (int i = 0; str[i]; i++) {

str[i] = tolower(str[i]);

}

}

int main() {

char str[] = "HELLO WORLD";

to_lower(str);

printf("%s\n", str);

return 0;

}

```

反转字符串

```c

include

include

void reverse_string(char *str) {

int len = strlen(str);

for (int i = 0; i < len / 2; i++) {

char temp = str[i];

str[i] = str[len - i - 1];

str[len - i - 1] = temp;

}

}

int main() {

char str[] = "hello world";

reverse_string(str);

printf("%s\n", str);

return 0;

}

```

调换两个字符串

```c

include

include

void swapStrings(char *a, char *b) {

char temp;

strcpy(temp, a);

strcpy(a, b);

strcpy(b, temp);

}

int main() {

char str1 = "Hello";

char str2 = "World";

printf("Before swap: str1 = %s, str2 = %s\n", str1, str2);

swapStrings(str1, str2);

printf("After swap: str1 = %s, str2 = %s\n", str1, str2);

return 0;

}

```

使用异或运算调换两个字符串

```c

include

include

void swapStrings(char *a, char *b) {

int length = strlen(a);

for (int i = 0; i < length; i++) {

a[i] = a[i] ^ b[i];

b[i] = a[i] ^ b[i];

a[i] = a[i] ^ b[i];

}

}

int main() {

char str1 = "Hello";

char str2 = "World";

printf("Before swap: str1 = %s, str2 = %s\n", str1, str2);

swapStrings(str1, str2);

printf("After swap: str1 = %s, str2 = %s\n", str1, str2);

return 0;

}

```

这些示例展示了如何在C语言中实现字符串的基本变换操作。根据具体需求，可以选择合适的方法来实现字符串的转换和处理。