Empty string: Difference between revisions
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=={{header|C}}== |
=={{header|C}}== |
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In C the strings are <code>char</code> pointers. A string terminates with the null char (U+0000, <code>'\0'</code>), which is not considered part of the string. Thus an empty string is <code>"\0"</code>, while a null string is a null pointer which points to nothing. |
In C the strings are <code>char</code> pointers. A string terminates with the null char (U+0000, <code>'\0'</code>), which is not considered part of the string. Thus an empty string is <code>"\0"</code>, while a null string is a null pointer which points to nothing. |
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<lang C> |
<lang C>#include <string.h> |
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/* ... */ |
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/* assign an empty string */ |
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const char *str = ""; |
const char *str = ""; |
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/* to test a null string */ |
/* to test a null string */ |
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if (str) { ... } |
if (str) { ... } |
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/* to test if string is empty */ |
/* to test if string is empty */ |
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if (str[0] == '\0') { ... } |
if (str[0] == '\0') { ... } |
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/* or equivalently use strlen function |
/* or equivalently use strlen function |
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strlen will seg fault on NULL pointer, so check first */ |
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/* or compare to a known empty string, same thing. "== 0" means strings are equal */ |
/* or compare to a known empty string, same thing. "== 0" means strings are equal */ |
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if (strcmp(str, "") == 0) { ... } |
if (strcmp(str, "") == 0) { ... } |
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