reading csv to struct [duplicate]

#include <stdio.h> #include <stdlib.h> #include <string.h> // this is needed to use strtok function (and strlen, strcpy) #define MAX_LEN 422498 #define MAX_KEY 128 struct record { char* a; char* b; }; int main(int argc, char **argv){ char* input=argv[1]; char* output=argv[2]; char buff[MAX_LEN]; // buff should be char[MAX_LEN], not char*[MAX_LEN] char *delimiter = ";"; //printf("%s\n",input); //printf("%s\n",output); FILE *fp; fp = fopen(input, "r"); //opening file*/ if( fp == NULL ) { perror("Error while opening the file.\n"); exit(EXIT_FAILURE); } int rowsNum=0; struct record* recArr = malloc(3 * sizeof (struct record)); //struct record recArr[4]; //recArr=malloc(1 * 2*sizeof(char*)); /*recArr[0].a="aa"; recArr[0].b="bb"; recArr[1].a="cc"; recArr[1].b="dd"; recArr[2].a="ee"; recArr[2].b="ff"; printf("%s\n", recArr[0].a); printf("%s\n\n", recArr[0].b); printf("%s\n", recArr[1].a); printf("%s\n\n", recArr[1].b); printf("%s\n", recArr[2].a); printf("%s\n\n", recArr[2].b);*/ while (fgets(buff, MAX_LEN, (FILE*)fp)!=NULL) { //recArr=realloc(recArr, (rowsNum+1) * 2*sizeof(char*)); //char* Key = strtok(buff, delimiter); //char* Value = strtok(NULL, delimiter); //recArr[rowsNum].a=strtok(buff, delimiter); //recArr[rowsNum].b=strtok(NULL, delimiter); // you have to COPY the string char* a=strtok(buff, delimiter); char* b=strtok(NULL, delimiter); recArr[rowsNum].a = malloc(sizeof(char) * (strlen(a) + 1)); // +1 for terminating '\0' recArr[rowsNum].b = malloc(sizeof(char) * (strlen(b) + 1)); strcpy(recArr[rowsNum].a, a); strcpy(recArr[rowsNum].b, b); printf("%s\n", recArr[rowsNum].a); printf("%s\n\n", recArr[rowsNum].b); /*Key=NULL; Value=NULL;*/ rowsNum++; printf("%d\n", rowsNum); } fclose(fp); int i; for (i=0;i<3;i++) { printf("%s\n", recArr[i].a); printf("%s\n\n", recArr[i].b); } //printf("%d\n", rowsNum); // you should free the allocated buffer for (i=0;i<3;i++) { free(recArr[i].a); free(recArr[i].b); } free(recArr); } 

• string.h should be included to use strtok : GCC made some warnings about it.
• the type of buff was not proper: it should be char buff[MAX_LEN], not char* buff[MAX_LEN](an extra asterisk is there)
• the function strtok modifies the buffer given and returns the pointer that is pointing somewhere in the buffer. When reading the next line, the buffer is overwritten and the text previously read is lost unless it is copied to somewhere. For that reason, I added some code that copies the strings read and save pointers that points where the strings are copied instead of somewhere in buff.