C指针char为小写

Question

我有指针数组，我想要lowerCase，我该怎么做？

char *myPointer = "HELLO MY NAME IS POINTER";

for(....)
    myPointer[i] = tolower(myPointer[i]);

我的应用程序崩溃了。 我需要使用指针！

谢谢

Answer 1

myPointer指向字符串文字，修改它为undefined behaviour。如果您想要修改它，可以使用数组：

char myPointer[]= "HELLO MY NAME IS POINTER";

Answer 2

查看tolower，它返回给定字符的小写版本。

char* myPointer = "OH MY HOST";

const int length = strlen( myPointer ); // get the length of the text
char* lower = ( char* )malloc( length + 1 ); // allocate 'length' bytes + 1 (for null terminator) and cast to char*
lower[ length ] = 0; // set the last byte to a null terminator

// copy all character bytes to the new buffer using tolower
for( int i = 0; i < length; i++ )
{
    lower[ i ] = tolower( myPointer[ i ] );
}