c / intermediate
Snippet
Precise String Searching with strcspn
The strcspn function calculates the length of the initial segment of a string that consists entirely of characters NOT in a specified set. It is highly efficient for finding the first occurrence of any character from a group of delimiters, returning the index where the first match is found.
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#include <stdio.h>#include <string.h>int main() {const char *csv_line = "data1,data2;data3";const char *delimiters = ",;";// Find length of segment NOT containing delimiterssize_t pos = strcspn(csv_line, delimiters);printf("First delimiter found at index: %zu\n", pos);if (csv_line[pos] != '\0') {printf("Delimiter was: '%c'\n", csv_line[pos]);}return 0;}
Breakdown
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const char *delimiters = ",;";
Defines a set of characters we want to search for.
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size_t pos = strcspn(csv_line, delimiters);
Returns the number of characters before any character in 'delimiters' appears.
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if (csv_line[pos] != '\0')
If the index is less than the string length, a delimiter was actually found.