Question

How to get the first line of a multi-line string in C

Answer 1

#include <stdio.h>
#include <string.h>

void getFirstLine(const char* multiLineString, char* firstLine) {
    const char* newline = strchr(multiLineString, '\n');
    
    if (newline != NULL) {
        size_t length = newline - multiLineString;
        strncpy(firstLine, multiLineString, length);
        firstLine[length] = '\0';
    } else {
        strcpy(firstLine, multiLineString);
    }
}

int main() {
    const char* multiLineString = 
        "First line\n"
        "Second line\n"
        "Third line\n"
        "Fourth line";
    
    char firstLine[256];
    
    getFirstLine(multiLineString, firstLine);
    
    printf("The first line is: %s\n", firstLine);
    
    return 0;
}


 
/*
run:
 
The first line is: First line
 
*/

 

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